Detailed explanation of the source code of JS mini game Space Fighter_javascript skills

The example in this article describes the source code of the space fighter of the JS mini-game and is shared with everyone for your reference. The specific introduction is as follows:

1. Game introduction:

This is a flight shooting game, vertical, with six levels in total.

2. Game requirements:

1. Fighters can fire bullets, and bullets can be upgraded by obtaining props.
2. Fighters can release bombs, and props can be obtained to increase the number.
3. Fighters can charge up to attack.
4. There are three types of props, namely upgrading bullets, increasing the number of bombs, and increasing the number of fighter planes.
5. Each level has different music.
6. After the fighter plane is shot down and then enters the battlefield, it will be protected.
7. Enemy aircraft AI design.

The game runs as shown below:

Complete example codeClick hereDownload from this site.

3. Javascript source code part:

/** 宇宙战机
*  Author: fdipzone
*  Date:  2013-02-12
*  Ver:  1.0
*/
window.onload = function(){
  var gameimg = [
    'images/fighter.png', 
    'images/fighter_p.png', 
    'images/fighter_s.png',
    'images/fighter_sp.png', 
    'images/shot.png', 
    'images/destroy.png', 
    'images/destroy_boss.png',
    'images/enemy.png', 
    'images/bullet.png', 
    'images/gift.png', 
    'images/bomb.png', 
    'images/boss1.png'];

  var callback = function(){
    var gameplane = $('gameplane');
    fighter.init();
    fighter.bgmove(gameplane);
  }
  img_preload(gameimg, callback);
};


/** fighter class */
var fighter = (function(){
  
  var hiscore = 10000;          // 最高分
  var score = 0;             // 当前分
  var fighternum = 3;           // 战机数量
  var bombnum = 3;            // 炸弹数量
  var ft = null;             // 战机对象
  var is_start = 0;            // 是否已开始游戏
  var is_bombing = 0;           // 是否爆炸中
  var is_lock = 1;            // 是否锁定
  var is_over = 0;            // 是否已结束
  var is_clear = 0;            // 清屏
  var is_pile = 0;            // 是否已达成蓄力
  var is_protect = 0;           // 是否保护状态
  var pilenum = 0;            // 已蓄力数量
  var ackey = {};             // 记录键是否按下
  var keypriority = {};          // 冲突键优先级
  var gamekey = [37,38,39,40,83,65];   // 游戏的按键
  var scoretag = [0,20,30,40,50,60,500]; // 不同敌机的分数
  var level = 1;             // 关数  
  var power = 1;             // 战机子弹威力
  var cheatcode = [];           // 记录cheat输入
  var failtimes = 0;           // 挑战失败次数
  
  // boss 数据
  var bossdata = [
          {'armor':500, 'left':136, 'top':-169, 'step':30},
          {'armor':1000, 'left':136, 'top':-169, 'step':30},
          {'armor':1500, 'left':136, 'top':-169, 'step':30},
          {'armor':2000, 'left':136, 'top':-169, 'step':30},
          {'armor':2500, 'left':136, 'top':-169, 'step':30},
          {'armor':3000, 'left':136, 'top':-169, 'step':30},
          ];

  // 出现的敌机
  var enemydata = [];

  // 当前出现的boss
  var curboss = null;
  
  // 关卡数据
  var map = [
    // level 1
    {
      'ms50':[[3, 680, 1, -50, 10, 10],[3, 680, 1, -50, 290, 10]], 
      'ms2500':[[3, 680, 1, -50, 70, 10],[3, 680, 1, -50, 220, 10]],
      'ms3500':[[1, 10, 12, -23, 190, 10]],
      'ms5500':[[3, 800, 2, 100, -50, 10]],
      'ms7500':[[3, 800, 2, 200, 450, -10]],
      'ms8000':[[1, 10, 11, -23, 100, 10]],
      'ms9500':[[3, 800, 2, 100, -50, 10]],
      'ms11500':[[3, 800, 2, 200, 450, -10]],
      'ms13500':[[3, 800, 2, 100, -50, 10]],
      'ms15500':[[3, 800, 3, -50, 30, 10],[3, 800, 3, -50, 340, 10]],
      'ms20000':[[3, 800, 3, -50, 90, 10],[3, 800, 3, -50, 280, 10]],
      'ms25000':[[1, 10, 4, 150, -50, 10],[1, 10, 4, 250, 400, -10],[1, 10, 4, 100, 400, -10]],
      'ms30000':[[3, 800, 5, 692, 90, -10],[3, 800, 5, 692, 280, -10]],
      'ms35000':[[3, 680, 1, -50, 70, 10],[3, 680, 1, -50, 220, 10]],
      'ms38000':[[1, 10, 11, -23, 10, 10]],
      'ms40000':[[1, 10, 4, 100, 400, -10],[1, 10, 4, 300, -50, 10]],
      'ms42500':[[3, 680, 1, -50, 70, 10],[3, 680, 1, -50, 220, 10]],
      'ms45500':[[3, 800, 2, 50, -50, 10]],
      'ms47500':[[3, 800, 2, 150, 450, -10]],
      'ms49500':[[3, 800, 2, 50, -50, 10]],
      'ms51500':[[3, 800, 2, 150, 450, -10]],
      'ms55500':[[3, 800, 3, -50, 90, 10],[3, 800, 3, -50, 280, 10]],
      'ms60000':[[3, 800, 3, -50, 30, 10],[3, 800, 3, -50, 340, 10]],
      'ms65000':[[1, 10, 4, 100, 400, -10],[1, 10, 4, 300, -50, 10]],
      'ms68000':[[3, 800, 5, 692, 110, -10],[3, 800, 5, 692, 260, -10]],
      'ms71000':[[1, 10, 13, -23, 220, 10]],
      'ms76000':[]
    },
    // level 2
    {
      'ms50':[[3, 680, 1, -50, 10, 10],[3, 680, 1, -50, 290, 10]], 
      'ms2500':[[3, 680, 1, -50, 70, 10],[3, 680, 1, -50, 220, 10]],
      'ms3500':[[1, 10, 12, -23, 190, 10]],
      'ms5500':[[3, 800, 2, 100, -50, 10]],
      'ms7500':[[3, 800, 2, 200, 450, -10]],
      'ms8000':[[1, 10, 11, -23, 100, 10]],
      'ms9500':[[3, 800, 2, 100, -50, 10]],
      'ms11500':[[3, 800, 2, 200, 450, -10]],
      'ms13500':[[3, 800, 2, 100, -50, 10]],
      'ms15500':[[3, 800, 3, -50, 30, 10],[3, 800, 3, -50, 340, 10]],
      'ms20000':[[3, 800, 3, -50, 90, 10],[3, 800, 3, -50, 280, 10]],
      'ms25000':[[1, 10, 4, 150, -50, 10],[1, 10, 4, 250, 400, -10],[1, 10, 4, 100, 400, -10]],
      'ms30000':[[3, 800, 5, 692, 90, -10],[3, 800, 5, 692, 280, -10]],
      'ms35000':[[3, 680, 1, -50, 70, 10],[3, 680, 1, -50, 220, 10]],
      'ms38000':[[1, 10, 11, -23, 10, 10]],
      'ms40000':[[1, 10, 4, 100, 400, -10],[1, 10, 4, 300, -50, 10]],
      'ms42500':[[3, 680, 1, -50, 70, 10],[3, 680, 1, -50, 220, 10]],
      'ms45500':[[3, 800, 2, 50, -50, 10]],
      'ms47500':[[3, 800, 2, 150, 450, -10]],
      'ms49500':[[3, 800, 2, 50, -50, 10]],
      'ms51500':[[3, 800, 2, 150, 450, -10]],
      'ms55500':[[3, 800, 3, -50, 90, 10],[3, 800, 3, -50, 280, 10]],
      'ms60000':[[3, 800, 3, -50, 30, 10],[3, 800, 3, -50, 340, 10]],
      'ms65000':[[1, 10, 4, 100, 400, -10],[1, 10, 4, 300, -50, 10]],
      'ms68000':[[3, 800, 5, 692, 110, -10],[3, 800, 5, 692, 260, -10]],
      'ms71000':[[1, 10, 13, -23, 220, 10]],
      'ms76000':[]
    },
    // level 3
    {
      'ms50':[[3, 680, 1, -50, 10, 10],[3, 680, 1, -50, 290, 10]], 
      'ms2500':[[3, 680, 1, -50, 70, 10],[3, 680, 1, -50, 220, 10]],
      'ms3500':[[1, 10, 12, -23, 190, 10]],
      'ms5500':[[3, 800, 2, 100, -50, 10]],
      'ms7500':[[3, 800, 2, 200, 450, -10]],
      'ms8000':[[1, 10, 11, -23, 100, 10]],
      'ms9500':[[3, 800, 2, 100, -50, 10]],
      'ms11500':[[3, 800, 2, 200, 450, -10]],
      'ms13500':[[3, 800, 2, 100, -50, 10]],
      'ms15500':[[3, 800, 3, -50, 30, 10],[3, 800, 3, -50, 340, 10]],
      'ms20000':[[3, 800, 3, -50, 90, 10],[3, 800, 3, -50, 280, 10]],
      'ms25000':[[1, 10, 4, 150, -50, 10],[1, 10, 4, 250, 400, -10],[1, 10, 4, 100, 400, -10]],
      'ms30000':[[3, 800, 5, 692, 90, -10],[3, 800, 5, 692, 280, -10]],
      'ms35000':[[3, 680, 1, -50, 70, 10],[3, 680, 1, -50, 220, 10]],
      'ms38000':[[1, 10, 11, -23, 10, 10]],
      'ms40000':[[1, 10, 4, 100, 400, -10],[1, 10, 4, 300, -50, 10]],
      'ms42500':[[3, 680, 1, -50, 70, 10],[3, 680, 1, -50, 220, 10]],
      'ms45500':[[3, 800, 2, 50, -50, 10]],
      'ms47500':[[3, 800, 2, 150, 450, -10]],
      'ms49500':[[3, 800, 2, 50, -50, 10]],
      'ms51500':[[3, 800, 2, 150, 450, -10]],
      'ms55500':[[3, 800, 3, -50, 90, 10],[3, 800, 3, -50, 280, 10]],
      'ms60000':[[3, 800, 3, -50, 30, 10],[3, 800, 3, -50, 340, 10]],
      'ms65000':[[1, 10, 4, 100, 400, -10],[1, 10, 4, 300, -50, 10]],
      'ms68000':[[3, 800, 5, 692, 110, -10],[3, 800, 5, 692, 260, -10]],
      'ms71000':[[1, 10, 13, -23, 220, 10]],
      'ms76000':[]
    },
    // level 4
    {
      'ms50':[[3, 680, 1, -50, 10, 10],[3, 680, 1, -50, 290, 10]], 
      'ms2500':[[3, 680, 1, -50, 70, 10],[3, 680, 1, -50, 220, 10]],
      'ms3500':[[1, 10, 12, -23, 190, 10]],
      'ms5500':[[3, 800, 2, 100, -50, 10]],
      'ms7500':[[3, 800, 2, 200, 450, -10]],
      'ms8000':[[1, 10, 11, -23, 100, 10]],
      'ms9500':[[3, 800, 2, 100, -50, 10]],
      'ms11500':[[3, 800, 2, 200, 450, -10]],
      'ms13500':[[3, 800, 2, 100, -50, 10]],
      'ms15500':[[3, 800, 3, -50, 30, 10],[3, 800, 3, -50, 340, 10]],
      'ms20000':[[3, 800, 3, -50, 90, 10],[3, 800, 3, -50, 280, 10]],
      'ms25000':[[1, 10, 4, 150, -50, 10],[1, 10, 4, 250, 400, -10],[1, 10, 4, 100, 400, -10]],
      'ms30000':[[3, 800, 5, 692, 90, -10],[3, 800, 5, 692, 280, -10]],
      'ms35000':[[3, 680, 1, -50, 70, 10],[3, 680, 1, -50, 220, 10]],
      'ms38000':[[1, 10, 11, -23, 10, 10]],
      'ms40000':[[1, 10, 4, 100, 400, -10],[1, 10, 4, 300, -50, 10]],
      'ms42500':[[3, 680, 1, -50, 70, 10],[3, 680, 1, -50, 220, 10]],
      'ms45500':[[3, 800, 2, 50, -50, 10]],
      'ms47500':[[3, 800, 2, 150, 450, -10]],
      'ms49500':[[3, 800, 2, 50, -50, 10]],
      'ms51500':[[3, 800, 2, 150, 450, -10]],
      'ms55500':[[3, 800, 3, -50, 90, 10],[3, 800, 3, -50, 280, 10]],
      'ms60000':[[3, 800, 3, -50, 30, 10],[3, 800, 3, -50, 340, 10]],
      'ms65000':[[1, 10, 4, 100, 400, -10],[1, 10, 4, 300, -50, 10]],
      'ms68000':[[3, 800, 5, 692, 110, -10],[3, 800, 5, 692, 260, -10]],
      'ms71000':[[1, 10, 13, -23, 220, 10]],
      'ms76000':[]
    },
    // level 5
    {
      'ms50':[[3, 680, 1, -50, 10, 10],[3, 680, 1, -50, 290, 10]], 
      'ms2500':[[3, 680, 1, -50, 70, 10],[3, 680, 1, -50, 220, 10]],
      'ms3500':[[1, 10, 12, -23, 190, 10]],
      'ms5500':[[3, 800, 2, 100, -50, 10]],
      'ms7500':[[3, 800, 2, 200, 450, -10]],
      'ms8000':[[1, 10, 11, -23, 100, 10]],
      'ms9500':[[3, 800, 2, 100, -50, 10]],
      'ms11500':[[3, 800, 2, 200, 450, -10]],
      'ms13500':[[3, 800, 2, 100, -50, 10]],
      'ms15500':[[3, 800, 3, -50, 30, 10],[3, 800, 3, -50, 340, 10]],
      'ms20000':[[3, 800, 3, -50, 90, 10],[3, 800, 3, -50, 280, 10]],
      'ms25000':[[1, 10, 4, 150, -50, 10],[1, 10, 4, 250, 400, -10],[1, 10, 4, 100, 400, -10]],
      'ms30000':[[3, 800, 5, 692, 90, -10],[3, 800, 5, 692, 280, -10]],
      'ms35000':[[3, 680, 1, -50, 70, 10],[3, 680, 1, -50, 220, 10]],
      'ms38000':[[1, 10, 11, -23, 10, 10]],
      'ms40000':[[1, 10, 4, 100, 400, -10],[1, 10, 4, 300, -50, 10]],
      'ms42500':[[3, 680, 1, -50, 70, 10],[3, 680, 1, -50, 220, 10]],
      'ms45500':[[3, 800, 2, 50, -50, 10]],
      'ms47500':[[3, 800, 2, 150, 450, -10]],
      'ms49500':[[3, 800, 2, 50, -50, 10]],
      'ms51500':[[3, 800, 2, 150, 450, -10]],
      'ms55500':[[3, 800, 3, -50, 90, 10],[3, 800, 3, -50, 280, 10]],
      'ms60000':[[3, 800, 3, -50, 30, 10],[3, 800, 3, -50, 340, 10]],
      'ms65000':[[1, 10, 4, 100, 400, -10],[1, 10, 4, 300, -50, 10]],
      'ms68000':[[3, 800, 5, 692, 110, -10],[3, 800, 5, 692, 260, -10]],
      'ms71000':[[1, 10, 13, -23, 220, 10]],
      'ms76000':[]
    },
    // level 6
    {
      'ms50':[[3, 680, 1, -50, 10, 10],[3, 680, 1, -50, 290, 10]], 
      'ms2500':[[3, 680, 1, -50, 70, 10],[3, 680, 1, -50, 220, 10]],
      'ms3500':[[1, 10, 12, -23, 190, 10]],
      'ms5500':[[3, 800, 2, 100, -50, 10]],
      'ms7500':[[3, 800, 2, 200, 450, -10]],
      'ms8000':[[1, 10, 11, -23, 100, 10]],
      'ms9500':[[3, 800, 2, 100, -50, 10]],
      'ms11500':[[3, 800, 2, 200, 450, -10]],
      'ms13500':[[3, 800, 2, 100, -50, 10]],
      'ms15500':[[3, 800, 3, -50, 30, 10],[3, 800, 3, -50, 340, 10]],
      'ms20000':[[3, 800, 3, -50, 90, 10],[3, 800, 3, -50, 280, 10]],
      'ms25000':[[1, 10, 4, 150, -50, 10],[1, 10, 4, 250, 400, -10],[1, 10, 4, 100, 400, -10]],
      'ms30000':[[3, 800, 5, 692, 90, -10],[3, 800, 5, 692, 280, -10]],
      'ms35000':[[3, 680, 1, -50, 70, 10],[3, 680, 1, -50, 220, 10]],
      'ms38000':[[1, 10, 11, -23, 10, 10]],
      'ms40000':[[1, 10, 4, 100, 400, -10],[1, 10, 4, 300, -50, 10]],
      'ms42500':[[3, 680, 1, -50, 70, 10],[3, 680, 1, -50, 220, 10]],
      'ms45500':[[3, 800, 2, 50, -50, 10]],
      'ms47500':[[3, 800, 2, 150, 450, -10]],
      'ms49500':[[3, 800, 2, 50, -50, 10]],
      'ms51500':[[3, 800, 2, 150, 450, -10]],
      'ms55500':[[3, 800, 3, -50, 90, 10],[3, 800, 3, -50, 280, 10]],
      'ms60000':[[3, 800, 3, -50, 30, 10],[3, 800, 3, -50, 340, 10]],
      'ms65000':[[1, 10, 4, 100, 400, -10],[1, 10, 4, 300, -50, 10]],
      'ms68000':[[3, 800, 5, 692, 110, -10],[3, 800, 5, 692, 260, -10]],
      'ms71000':[[1, 10, 13, -23, 220, 10]],
      'ms76000':[]
    }
  ];


  // 初始化
  init = function(){
    ft = $('fighter');
    reset();
    key_event();
  }


  // 开始游戏
  start = function(){
    is_clear = 0;
    is_protect = 0;
    disp(ft.id, 'show');
    reset_fighter();
    reset_pile();
    process();
    bgsound(level, true);
    bgchange(level);
    fighter_init();
  }


  // 设置事件
  key_event = function(){

    document.onkeydown = function(e){
      var e = e || window.event;
      var curkey = e.keyCode || e.which || e.charCode;

      if(is_start==0){ 
        if(cheatcode.length>12){
          cheatcode.shift();
        }
        cheatcode.push(curkey); // 记录用户输入的cheatcode
      }
      
      if(is_start==1 && in_array(curkey,gamekey)){
        if(ackey[curkey.toString()]==0 || typeof(ackey[curkey.toString()])=='undefined' || !in_array(curkey,[83,65])){  // 射击与炸弹连按屏蔽
          ackey[curkey.toString()] = 1;  // save key down
          switch(curkey){
            case 37:
            case 39:
              keypriority.left = curkey;  // left right
              break;
            case 38:
            case 40:
              keypriority.top = curkey;  // up down
              break;
          }
        }else{
          return false;
        }
      }
      
      if(curkey==13 || is_start==1 && is_lock==0){  // game is start or key=13
        switch(curkey){
          case 13: // enter
            if(is_start==0){
              is_start=1;
              disp('op', 'hide');
              msg_show();
              setTimeout(function(){
                msg_hide();
                cheat();
                start();
              }, 1500);
            }
            break;

          case 83: // 射击
            shot();
            break;

          case 65: // 炸弹
            bomb();
            break;
        }
      }
    }

    document.onkeyup = function(e){
      var e = e || window.event;
      var curkey = e.keyCode || e.which || e.charCode;
      if(is_start==1 && in_array(curkey,gamekey)){
        ackey[curkey.toString()] = 0;  // release key down
        
        if(curkey==83){// 释放蓄力攻击
          if(is_pile==1){
            pile_shot();
          }
          reset_pile();
        }
      }
    }

  }


  // 循环执行的动作
  action = function(){
    var movestep = 5;  // 移动步长
    var et = setInterval(function(){
      if(is_start==0 || is_lock==1){
        clearInterval(et);
      }
      
      // 移动
      if(ackey['37']==1 && (ackey['39']==0 || keypriority.left==37)){  // 冲突时判断优先级
        if(getPosition(ft,'left')<movestep){
          setPosition(ft, 'left', 0);  // left
        }else{
          setPosition(ft, 'left', getPosition(ft,'left') - movestep);
        }
      }
      if(ackey['38']==1 && (ackey['40']==0 || keypriority.top==38)){
        if(getPosition(ft, 'top')<movestep){
          setPosition(ft, 'top', 0);  // top
        }else{
          setPosition(ft, 'top', getPosition(ft,'top') - movestep);
        }
      }
      if(ackey['39']==1 && (ackey['37']==0 || keypriority.left==39)){
        if(400-(getPosition(ft,'left')+50)<movestep){
          setPosition(ft, 'left', 350);  //width-fighter.width
        }else{
          setPosition(ft, 'left', getPosition(ft,'left') + movestep);
        }
      }
      if(ackey['40']==1 && (ackey['38']==0 || keypriority.top==40)){
        if(640-(getPosition(ft,'top')+50)<movestep){
          setPosition(ft, 'top', 590);  // height-fighter.height
        }else{
          setPosition(ft, 'top', getPosition(ft,'top') + movestep);
        }
      }

      // 蓄力攻击
      if(ackey['83']==1){
        if(pilenum<1000){
          pilenum = pilenum + 20;
        }else if(is_pile==0){
          is_pile = 1;
          if(is_protect==1){
            setClass(ft, 'fighter_sp');
          }else{
            setClass(ft, 'fighter_s');
          }
        }
      }

    }, 20);
  }


  // 战机射击
  shot = function(){
    // 创建子弹
    var bullet = document.createElement('div');
    var offsetx;

    switch(power){
      case 1:
        offsetx = 20;
        break;
      case 2:
        offsetx = 15;
        break;
      case 3:
        offsetx = 10;
        break;
      case 4:
        offsetx = 4;
        break;
    }

    setClass(bullet, 'shot' + power);

    // 设置子弹初始位置
    setPosition(bullet, 'top', getPosition(ft, 'top')-30);
    setPosition(bullet, 'left', getPosition(ft, 'left') + offsetx);
    
    ft.parentNode.appendChild(bullet);
    
    // 设置子弹运动
    var et = setInterval(function(){
      if(getPosition(bullet,'top')<=-30 || is_lock==1){
        clearInterval(et);
        ft.parentNode.removeChild(bullet);  // 释放子弹
      }

      for(var i=0; i<enemydata.length; i++){
        if(enemydata[i]!=null){
          if(impact(bullet, enemydata[i])){  // 打中敌机
            destroy(enemydata[i]);
            scoreup(enemydata[i].type);
            enemydata[i] = null;
            clearInterval(et);
            ft.parentNode.removeChild(bullet);
          }
        }
      }

      if(curboss!=null){  // boss 战
        if(impact(bullet, curboss['obj'])){ // 打中boss
          curboss['armor']=parseInt(curboss['armor'])-power*10;
          clearInterval(et);
          ft.parentNode.removeChild(bullet);
        }
      }

      setPosition(bullet, 'top', getPosition(bullet, 'top')-15);

    }, 30)
  }


  // 蓄力射击
  pile_shot = function(){
    var pilebullet = document.createElement('div');
    setClass(pilebullet, 'pileshot');

    // 设置子弹初始位置
    setPosition(pilebullet, 'top', getPosition(ft, 'top')-30);
    setPosition(pilebullet, 'left', getPosition(ft, 'left'));
    
    ft.parentNode.appendChild(pilebullet);

    var et = setInterval(function(){
      if(getPosition(pilebullet,'top')<=-85 || is_lock==1){
        clearInterval(et);
        ft.parentNode.removeChild(pilebullet); // 释放子弹
      }

      for(var i=0; i<enemydata.length; i++){
        if(enemydata[i]!=null){
          if(impact(pilebullet, enemydata[i])){  // 打中敌机
            destroy(enemydata[i]);
            scoreup(enemydata[i].type);
            enemydata[i] = null;
          }
        }
      }

      if(curboss!=null){  // boss 战
        if(impact(pilebullet, curboss['obj'])){ // 打中boss
          curboss['armor']=parseInt(curboss['armor'])-100;
          clearInterval(et);
          ft.parentNode.removeChild(pilebullet); // 释放子弹
        }
      }

      setPosition(pilebullet, 'top', getPosition(pilebullet, 'top')-20);

    }, 30)
  }


  // 放炸弹
  bomb = function(){
    if(is_bombing==0 && bombnum>0){  // 不是爆炸中且有炸弹数
      is_bombing = 1;
      bombnum --;
      setHtml('bombnum', bombnum);  // 自减1

      var opacity = 100;
      setOpacity($('bomb'), opacity);
      disp('bomb', 'show');

      // 清除所有敌机及敌方子弹
      is_clear = 1;

      // 打击boss
      if(curboss!=null){
        curboss['armor'] = parseInt(curboss['armor'])-300;
      }

      var step = 0;
      var et = setInterval(function(){  // 炸弹效果
        if(step<11){
          setBgPosition($('bomb'), 0, step*(-280));
        }else{
          clearInterval(et);
          disp('bomb', 'hide');
          is_bombing = 0;
          is_clear = 0;
        }
        step ++;
      }, 70);
    }
  }


  // 游戏进程
  process = function(){
    var leveldata = map[level-1], processed = 0, step = 10;
    var levelstep = 0;  // 每关开始清0
    var et = setInterval(function(){
      if(is_lock==0){
        processed += step;
        if(attrcount(leveldata)>levelstep){  // 未完成本关
          if(leveldata['ms'+processed]){
            for(var i=0; i<leveldata['ms'+processed].length; i++){
              var msdata = leveldata['ms'+processed][i];
              create(msdata);
            }
            levelstep ++;  // 进度
          }
        }else{  // 已完成本关,进入Boss战
          bosswar();
          clearInterval(et);
        }
      }

      if(is_over==1){
        clearInterval(et);
      }

    }, step);
  }


  /* 创建关卡元素
  /* msdata:{
    num:出现的数量
    interval:间隔
    type:类型
    top:原始top坐标
    left:原始left坐标
    step:移动距离
    }
  */
  create = function(msdata){
    var num = msdata[0],
      interval = msdata[1],
      type = msdata[2],
      top = msdata[3],
      left = msdata[4],
      step = msdata[5];

    var et = setInterval(function(){
        if(num>0){
          var enft = document.createElement('div');
          setClass(enft, 'element' + type);
          enft.type = type;
          setPosition(enft, 'top', top);
          setPosition(enft, 'left', left);
          ft.parentNode.appendChild(enft);
          if(type<=10){
            enemydata.push(enft);
          }
          route(enft, type, step);
          num--;
        }else{
          clearInterval(et);
        }
      }, interval);
  }


  // 元素运动轨迹
  route = function(enft, type, step){
    var et = null;
    switch(type){
      case 1: // 曲线
        var count = 0;
        et = setInterval(function(){
          if(node_exist(enft)){
            setPosition(enft, 'top', getPosition(enft,'top')+Math.abs(step));
            setPosition(enft, 'left', getPosition(enft,'left')+step);
            count<5&#63; count++ : (count=0, step*=-1);
            if(getPosition(enft, 'top')>640 || is_over==1 || is_clear==1){
              clearInterval(et);
              ft.parentNode.removeChild(enft);
            }
            impact_handle(enft, et);
          }else{
            clearInterval(et);
          }
        }, 80);
        break;

      case 2: // 横向
        var count = 0;
        et = setInterval(function(){
          if(node_exist(enft)){
            setPosition(enft, 'left', getPosition(enft,'left')+step);
            count<9&#63; count++ : (count=0, attack(enft,1,17,47));
            if(getPosition(enft,'left')>400 && step>0 || getPosition(enft,'left')<-50 && step<0 || is_over==1 || is_clear==1){
              clearInterval(et);
              ft.parentNode.removeChild(enft);
            }
            impact_handle(enft, et);
          }else{
            clearInterval(et);
          }
        }, 80);
        break;

      case 3: // 竖向
        var count = 0;
        et = setInterval(function(){
          if(node_exist(enft)){
            setPosition(enft, 'top', getPosition(enft,'top')+step);
            count<9&#63; count++ : (count=0, attack(enft,1,17,47));
            if(getPosition(enft,'top')>640 || is_over==1 || is_clear==1){
              clearInterval(et);
              ft.parentNode.removeChild(enft);
            }
            impact_handle(enft, et);
          }else{
            clearInterval(et);
          }
        }, 75);
        break;

      case 4: // 左右循环移动攻击
        var count = 0;
        et = setInterval(function(){
          if(node_exist(enft)){
            setPosition(enft, 'left', getPosition(enft,'left')+step);
            count<10&#63; count++ : (count=0, attack(enft,4,17,31));
            
            if(getPosition(enft,'left')>=350 && step>0 || getPosition(enft,'left')<=0 && step<0){
              step*=-1;
            }

            if(is_over==1 || is_clear==1){
              clearInterval(et);
              ft.parentNode.removeChild(enft);
            }
            impact_handle(enft, et);
          }else{
            clearInterval(et);
          }
        }, 80);
        break;

      case 5: // 从后面攻击
        var count = 0;
        et = setInterval(function(){
          if(node_exist(enft)){
            setPosition(enft, 'top', getPosition(enft,'top')+step);
            count<9&#63; count++ : (count=0, attack(enft,1,17,-17));
            if(getPosition(enft,'top')<-32 || is_over==1 || is_clear==1){
              clearInterval(et);
              ft.parentNode.removeChild(enft);
            }
            impact_handle(enft, et);
          }else{
            clearInterval(et);
          }
        }, 75);
        break;

      case 11: // power gift
        var count = 0;
        et = setInterval(function(){
          if(node_exist(enft)){
            setPosition(enft, 'top', getPosition(enft,'top')+Math.abs(step));
            setPosition(enft, 'left', getPosition(enft,'left')+step);
            count<5&#63; count++ : (count=0, step*=-1);
            if(getPosition(enft, 'top')>640 || is_over==1){
              clearInterval(et);
              ft.parentNode.removeChild(enft);
            }
            if(impact(enft, ft) && is_lock==0){  // 奖励与战机相撞
              powerup();
              ft.parentNode.removeChild(enft);
              clearInterval(et);
            }
          }else{
            clearInterval(et);
          }
        }, 80);
        break;

      case 12: // bomb gift
        var count = 0;
        et = setInterval(function(){
          if(node_exist(enft)){
            setPosition(enft, 'top', getPosition(enft,'top')+Math.abs(step));
            setPosition(enft, 'left', getPosition(enft,'left')+step);
            count<5&#63; count++ : (count=0, step*=-1);
            if(getPosition(enft, 'top')>640 || is_over==1){
              clearInterval(et);
              ft.parentNode.removeChild(enft);
            }
            if(impact(enft, ft) && is_lock==0){  // 奖励与战机相撞
              bombup();
              ft.parentNode.removeChild(enft);
              clearInterval(et);
            }
          }else{
            clearInterval(et);
          }
        }, 80);
        break;

      case 13: // fighter gift
        var count = 0;
        et = setInterval(function(){
          if(node_exist(enft)){
            setPosition(enft, 'top', getPosition(enft,'top')+Math.abs(step));
            setPosition(enft, 'left', getPosition(enft,'left')+step);
            count<5&#63; count++ : (count=0, step*=-1);
            if(getPosition(enft, 'top')>640 || is_over==1){
              clearInterval(et);
              ft.parentNode.removeChild(enft);
            }
            if(impact(enft, ft) && is_lock==0){  // 奖励与战机相撞
              fighterup();
              ft.parentNode.removeChild(enft);
              clearInterval(et);
            }
          }else{
            clearInterval(et);
          }
        }, 80);
        break;
    }
  }


  // 销毁
  destroy = function(dobj){  // dobj:被销毁的对象
    var dest = document.createElement('div');
    setClass(dest, 'destroy');
    setPosition(dest, 'top', getPosition(dobj, 'top'));
    setPosition(dest, 'left', getPosition(dobj, 'left'));
    ft.parentNode.appendChild(dest);

    if(dobj.id=='fighter'){  // 战机被击中
      disp(dobj.id, 'hide');
      power = 1;
      bombnum = 3;
      fighternum--;
      setHtml('fighternum', fighternum);
      setHtml('bombnum', bombnum);
      is_lock = 1;
    }else{
      dobj.parentNode.removeChild(dobj);
    }
    
    var step = 0;
    var et = setInterval(function(){
      if(step<11){
        setBgPosition(dest, step*(-48), 0);
        step++;
      }else{
        if(dobj.id=='fighter'){
          setTimeout(function(){
            if(fighternum>0){
              levelcontinue();
            }else{
              if(curboss!=null){
                obj = curboss['obj'];
                obj.parentNode.removeChild(obj);
              }
              gameover();  //战机全部被击中,游戏结束
            }
          },1000);
        }
        dest.parentNode.removeChild(dest);
        clearInterval(et);
      }
    }, 50);
  }


  // boss war
  bosswar = function(){
    var boss = bossdata[level-1];
    var bossft = document.createElement('div');
    setClass(bossft, 'boss' + level);
    setPosition(bossft, 'left', boss['left']);
    setPosition(bossft, 'top', boss['top']);
    ft.parentNode.appendChild(bossft);
    
    curboss = {"armor":boss['armor'],"obj":bossft};

    switch(level){
      case 1: // boss 1
      case 2: // boss 2
      case 3: // boss 3
      case 4: // boss 4
      case 5: // boss 5
      case 6: // boss 6
        var step = -3;
        var count = 0;
        var et = setInterval(function(){
          if(getPosition(bossft,'top')<50){  // boss 进场
            setPosition(bossft, 'top', getPosition(bossft, 'top')+5);
          }else{

            if(curboss['armor']<=0){  // boss over
              clearInterval(et);
              bossover();
            }else{

              if(step<0){ // 左移动
                if(getPosition(bossft,'left')>10){
                  setPosition(bossft, 'left', getPosition(bossft, 'left')+step);
                }else{
                  step*=-1;
                }
              }

              if(step>0){ // 右移动
                if(getPosition(bossft,'left')<260){
                  setPosition(bossft, 'left', getPosition(bossft, 'left')+step);
                }else{
                  step*=-1;
                }
              }

              if(count>=35 && count%35==0){
                 attack(bossft, 1, 30, 30);
                 attack(bossft, 1, 80, 30);
              }
              
              if(count>=60 && count%60==0){
                attack(bossft, 2, 15, 75);
                attack(bossft, 2, 105, 75);
              }

              if(count>=100 && count%100==0){
                attack(bossft, 3, 60, 92);
              }

              count<8400&#63; count++ : count=0;

            }
          }
        }, boss['step']);
        break;
    }
  }


  /* attack
  * obj 敌机
  * type 攻击类型
  * left 子弹初始left
  * top 子弹初始top
  */
  attack = function(obj, type, left, top){
    if(is_lock==1){
      return false;  // 如已锁定不射击
    }

    var oleft = getPosition(obj, 'left')+left;
    var otop = getPosition(obj, 'top')+top;

    switch(type){

      case 1: //向战机攻击

        // 子弹初始位置与战机位置
        var opoint = {x:oleft+7, y:otop+7};
        var dpoint = {x:getPosition(ft,'left')+25, y:getPosition(ft,'top')+25};
        var p = vector(opoint, dpoint, 8);

        enftbullet('bullet', oleft, otop, p[0], p[1], 35);
        break;

      case 2: //直线攻击
        var num = 3;
        var st = setInterval(function(){
          if(num>0){
            enftbullet('bullet', oleft, otop, 0, 8, 35);
            num --;

          }else{
            clearInterval(st);
          }
        }, 150);
        break;

      case 3: // 散开攻击
        var num = 3;
        var st = setInterval(function(){
          if(num>0){
            switch(num){
              case 1:
                enftbullet('sbullet', oleft, otop, 0, 8, 35);
                break;

              case 2:
                enftbullet('sbullet', oleft, otop, 3, 8, 35);
                break;

              case 3:
                enftbullet('sbullet', oleft, otop, -3, 8, 35);
                break;
            }

            num --;

          }else{
            clearInterval(st);
          }
        }, 0);
        break;

      case 4: // 小散开攻击
        var num = 3;
        var st = setInterval(function(){
          if(num>0){
            switch(num){
              case 1:
                enftbullet('bullet', oleft, otop, 0, 8, 35);
                break;

              case 2:
                enftbullet('bullet', oleft, otop, 3, 8, 35);
                break;

              case 3:
                enftbullet('bullet', oleft, otop, -3, 8, 35);
                break;
            }

            num --;

          }else{
            clearInterval(st);
          }
        }, 0);
        break;
    }
  }


  /* enft bullet
  * type 子弹类型
  * oleft,otop 子弹初始位置
  * left,top 子弹徧移
  * speed 速度
  */
  enftbullet = function(type, oleft, otop, left, top, speed){
    var bullet = document.createElement('div');
    setClass(bullet, type);
    setPosition(bullet, 'left', oleft);
    setPosition(bullet, 'top', otop);
    ft.parentNode.appendChild(bullet);

    var et = setInterval(function(){
      setPosition(bullet, 'top', getPosition(bullet,'top')+top);
      setPosition(bullet, 'left', getPosition(bullet,'left')+left);

      if(getPosition(bullet,'left')>400 || getPosition(bullet,'left')<-30 || getPosition(bullet,'top')<-30 || getPosition(bullet,'top')>640 || is_lock==1 || is_clear==1){
        clearInterval(et);
        ft.parentNode.removeChild(bullet);
      }

      impact_handle(bullet, et);
    }, speed);
  }


  // boss over
  bossover = function(){
    obj = curboss['obj'];
    obj.parentNode.removeChild(obj);

    scoreup(6); // boss score

    var dest = document.createElement('div');
    setClass(dest, 'destroyboss');
    setPosition(dest, 'top', getPosition(obj, 'top'));
    setPosition(dest, 'left', getPosition(obj, 'left'));
    ft.parentNode.appendChild(dest);

    var step = 0;
    var et = setInterval(function(){
      if(step<21){
        setBgPosition(dest, step*(-150), 0);
      }else if(step==21){
        dest.parentNode.removeChild(dest);
      }else if(step==50){
        clearInterval(et);
        levelup();
      }
      step++;
    }, 50);
  }


  // continue
  levelcontinue = function(){
    reset_fighter();
    disp(ft.id, 'show');
    setProtect();
    fighter_init();
  }


  // 过关
  levelup = function(){
    keypriority = {};
    enemydata = [];
    curboss = null;
    level ++;

    bgsound('pass', false);

    var processed = 0;
    var et = setInterval(function(){
      is_lock = 1;
      processed = processed + 15;
      
      if(getPosition(ft, 'top')>-50){
        setPosition(ft, 'top', getPosition(ft, 'top')-15);
      }
      
      if(processed>=2500){
        clearInterval(et);
        disp(ft.id, 'hide');
        
        if(level<=map.length){
          bgchange(0);
          msg_show();
          setTimeout(function(){
            msg_hide();
            start();
          }, 1500);
        }else{
          gameclear();  // 通关
        }
      }
    }, 25);
  }


  // 更新分数
  scoreup = function(type){
    if(typeof(scoretag[type])!='undefined'){
      score = score + scoretag[type] * level;
      setHtml('score', score);
      if(score > hiscore){
        hiscore = score;
        setHtml('hiscore', hiscore);
      }
    }
  }


  // 子弹升级
  powerup = function(){
    power = power+1>4&#63; 4 : power+1;
  }  


  // 炸弹增加
  bombup = function(){
    bombnum ++;
    setHtml('bombnum', bombnum);
  }


  // 战机增加
  fighterup = function(){
    fighternum ++;
    setHtml('fighternum', fighternum);
  }


  // 保护状态
  setProtect = function(){
    is_protect = 1;
    if(is_pile==1){
      setClass(ft, 'fighter_sp');
    }else{
      setClass(ft, 'fighter_p');
    }
    setTimeout(function(){
      is_protect = 0;
      if(is_pile==1){
        setClass(ft, 'fighter_s');
      }else{
        setClass(ft, 'fighter');
      }
    }, 3000)
  }


  // 碰撞处理
  impact_handle = function(obj, et){  // et 定时器
    if(impact(obj, ft) && is_lock==0){  // 产生碰撞
      if(is_protect==0){
        destroy(ft);
        clearInterval(et);
        ft.parentNode.removeChild(obj);
      }
    }
  }


  // 全部通关
  gameclear = function(){
    is_over = 1;
    disp('gameclear', 'show');
    setHtml('clearcon', 'Game Clear' + '<br>' + 'SCORE : ' + score);
    bgsound('clear', false);
    bgchange('clear');
    setTimeout(function(){
      bgsound();
      init();
    }, 16000);
  }


  // 游戏结束
  gameover = function(){
    is_over = 1;
    disp('gameover', 'show');
    setHtml('overcon', 'LEVEL : ' + level + '<br>' + 'SCORE : ' + score);
    bgsound('over', false);
    bgchange('over');
    failtimes++;
    setTimeout(function(){
      if(failtimes==3){
        alert('在游戏开始画面依次输入 ↑ ↑ ↓ ↓ ← → ← → a s a s，再开始游戏，会有惊喜^_^');
      }
      bgsound();
      init();
    }, 8000);
  }


  // 显示讯息
  msg_show = function(){
    setHtml('level', 'LEVEL - ' + level);
    disp('level', 'show');
    is_lock = 1;
  }


  // 隐藏讯息
  msg_hide = function(){
    disp('level', 'hide');
  }


  // 重置
  reset = function(){
    is_start = 0;
    is_bombing = 0;
    is_lock = 1;
    is_over = 0;
    is_clear = 0;
    is_protect = 0;
    level = 1;
    power = 1;
    ackey = {};
    keypriority = {};
    enemydata = [];
    score = 0;
    fighternum = 3;
    bombnum = 3;

    setHtml('hiscore', hiscore);
    setHtml('score', score);
    setHtml('fighternum', fighternum);
    setHtml('bombnum', bombnum);

    reset_fighter();
    reset_pile();

    disp('op', 'show');
    disp('gameover', 'hide');
    disp('gameclear', 'hide');

    bgchange(0);
  }


  // 重置战机位置
  reset_fighter = function(){
    setPosition(ft, 'top', 640);
    setPosition(ft, 'left', 175);
    setClass(ft, 'fighter');
  }


  // 重置蓄力
  reset_pile = function(){
    is_pile = 0;
    pilenum = 0;
    if(is_protect==1){
      setClass(ft, 'fighter_p');
    }else{
      setClass(ft, 'fighter');
    }
  }


  // 战机初始化
  fighter_init = function(){
    var et = setInterval(function(){
      if(getPosition(ft, 'top')>400){
        setPosition(ft, 'top', getPosition(ft, 'top')-12);
      }else{
        clearInterval(et);
        is_lock = 0;
        action();
      }
    }, 30);
  }


  // 密技30命
  cheat = function(){
    if(cheatcode.join(',')=='38,38,40,40,37,39,37,39,65,83,65,83,13'){
      fighternum = 30;
      setHtml('fighternum', fighternum);
    }
    cheatcode = [];
  }


  // 背景控制
  bgmove = function(obj){
    var step = 1;
    var et = setInterval(function(){
      var bgpos = getBgPosition(obj);
      if(bgpos['top']==640){
        setBgPosition(obj, 0, 0);  // reset
      }else{
        setBgPosition(obj, bgpos['left'], bgpos['top']+step);
      }
    }, 50);
  }


  // 背景切换
  bgchange = function(file){
    var obj = $('gameplane');
    setClass(obj, 'gameplane bg'+file);
  }


  // 音乐控制
  bgsound = function(file, loop){
        var id = 'audioplayer';
        
        if(typeof(file)!='undefined'){
            if(typeof(loop)=='undefined'){
                loop = false;
            }

            var audiofile = [];
            audiofile['mp3'] = 'music/' + file + '.mp3';
            audiofile['ogg'] = 'music/' + file + '.ogg';
            audioplayer(id, audiofile , loop);
        }else{
            audioplayer(id);
        }
  }

  return this;

})();

I believe that what is described in this article has certain reference value for everyone’s JavaScript game design.