Example analysis of using JavaScript to generate lottery numbers-JS Tutorial-php.cn

This "Lottery Number Generator" is purely front-end development, involving HTML, JS, and CSS. For the sake of simplicity, all the codes are written into an html file. The advantage of this is that the file can be opened directly with a browser. Of course, in actual work, it is best to put them in different files. The entire area is placed in a large p tag, which appears as a rectangular area, and the display position is controlled through JS; set up a drop-down list, and you can choose to generate 1-5 groups of random numbers. When the button is clicked , you can generate numbers corresponding to the number of groups; the number area is divided into two parts. The upper part is a randomly generated unordered number, and the lower part is a number after sorting these unordered numbers. The number of generated groups is controlled by the drop-down list above. The core of this tool is to generate random numbers and sort the random numbers, both of which are implemented through JS code. Here are some important JS codes.

Generate random numbers: Lotto is divided into front area numbers and rear area numbers. The front area numbers are 5 numbers from 01-35 without repetition, and the rear area numbers are from 01-12 without repetition. Take 2 numbers to form a set of 7-digit numbers. Two arrays are defined here: arr35 stores the 01-35 numbers in the front area, and arr12 stores the 01-12 numbers in the back area. Use the "temp = Math.floor(Math.random()*arr35.length)" method to take a random number from 0-arr35.length as the index, and use arr35[temp] to get the value of the index position in the array, also It is a random number, and then dynamically added to the span before sorting by getting the id. After fetching, use "arr35.splice(temp,1);" to delete the random number in the array and reduce the length of the array by one. Loop 5 times to get 5 random numbers from 01-35 without repetition, and the same goes for the next two digits.

var arr35 = ["01","02","03","04","05","06","07","08","09","10","11","12","13","14","15","16","17",                           
"18","19","20","21","22","23","24","25","26","27","28","29","30","31","32","33","34","35"];
var arr12 = ["01","02","03","04","05","06","07","08","09","10","11","12"];
var span = "";
var temp = "";
for(var i=1;i<6;i++){
    span = "span" + x + i;
    temp = Math.floor(Math.random()*arr35.length);//随机取一个数
    document.getElementById(span).innerText = arr35[temp];
    document.getElementById(span).style.backgroundColor = "red";
    arr35.splice(temp,1);//删除该位置的值}

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Random number sorting: The insertion sort algorithm is used here, which only sorts the first five digits of each group of numbers. The amount of data is very small. After sorting, the id is dynamically added to the sorted span by obtaining the id.

//插入排序
function bubbleSort(array){    
var len = array.length;    
for (var i = 0; i < len; i++) {        
for (var j = i; j > 0 && array[j]<array[j-1]; j--) {            
var swap = array[j];  //第二个for循环使元素比较并移动到合适位置
            array[j] = array[j-1];
            array[j-1] = swap;
        }
    }    return array;
}

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The remaining JS, HTML, and CSS technologies will not be introduced in detail.

Complete code:

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>大乐透号码生成器</title>
<style type="text/css">
#table{
width:800px; 
height:500px;
margin:10px;
border:2px 
solid 
#000000;
box-shadow: 10px 10px 5px;border-radius:50px;}
.buttonStyle{height:40px;margin:20px;font-size:20px;background-color:#6495ED;color:white;border-radius:10px;}
.oneStyle{margin-left:200px;margin-top:10px;font-family:sans-serif;font-size:20px;}
span{border-radius: 50%;color: #FFFFFF;padding:3px;font-size:13px;}
</style>
</head>
<body>
    <p id="table">
        <p>
            <h1 style="text-align:center">大乐透号码生成器</h1>
        </p>
        <p class="oneStyle">
                        生成组数：<select id="zushu" style="width:150px;height:30px;margin:10px;" onchange="select()">
                        <option value="1">生成 1 组号码</option>
                        <option value="2">生成 2 组号码</option>
                        <option value="3">生成 3 组号码</option>
                        <option value="4">生成 4 组号码</option>
                        <option value="5">生成 5 组号码</option>
                    </select>
        </p>
        <p class="oneStyle">
        随机号码1：<span id="span11"></span> <span id="span12"></span> <span id="span13"></span> 
        <span id="span14"></span> <span id="span15"></span>
           <span id="span16"></span> <span id="span17"></span><br>
        随机号码2：<span id="span21"></span> <span id="span22"></span> <span id="span23"></span> 
        <span id="span24"></span> <span id="span25"></span>
           <span id="span26"></span> <span id="span27"></span><br>
        随机号码3：<span id="span31"></span> <span id="span32"></span> <span id="span33"></span> 
        <span id="span34"></span> <span id="span35"></span>
           <span id="span36"></span> <span id="span37"></span><br>
        随机号码4：<span id="span41"></span> <span id="span42"></span> <span id="span43"></span> 
        <span id="span44"></span> <span id="span45"></span>
           <span id="span46"></span> <span id="span47"></span><br>
        随机号码5：<span id="span51"></span> <span id="span52"></span> <span id="span53"></span> 
        <span id="span54"></span> <span id="span55"></span>
           <span id="span56"></span> <span id="span57"></span><br>
        </p>
        <p class="oneStyle">
        排序后码1：<span id="span61"></span> <span id="span62"></span> <span id="span63"></span> 
        <span id="span64"></span> <span id="span65"></span>
           <span id="span66"></span> <span id="span67"></span><br>
        排序后码2：<span id="span71"></span> <span id="span72"></span> <span id="span73"></span> 
        <span id="span74"></span> <span id="span75"></span>
           <span id="span76"></span> <span id="span77"></span><br>
        排序后码3：<span id="span81"></span> <span id="span82"></span> <span id="span83"></span> 
        <span id="span84"></span> <span id="span85"></span>
           <span id="span86"></span> <span id="span87"></span><br>
        排序后码4：<span id="span91"></span> <span id="span92"></span> <span id="span93"></span> 
        <span id="span94"></span> <span id="span95"></span>
           <span id="span96"></span> <span id="span97"></span><br>
        排序后码5：<span id="span101"></span> <span id="span102"></span> <span id="span103"></span> 
        <span id="span104"></span> <span id="span105"></span>
           <span id="span106"></span> <span id="span107"></span><br>
        </p>
        <p style="text-align:center">
            <input class="buttonStyle" id="fiveNumber" type="button" onclick="number()">
        </p>
    </p>
    <script type="text/javascript">
        var table = document.getElementById("table");        
        var width = document.documentElement.clientWidth;  //浏览器可见区域宽
        var height = document.documentElement.clientHeight;  //浏览器可见区域高        
        table.style.marginLeft = ((width-800)/2)+"px";        
        table.style.marginTop = ((height-700)/2)+"px";
        var val = "1";
        document.getElementById("fiveNumber").setAttribute("title","生成 1 组号码");
        document.getElementById("fiveNumber").setAttribute("value","生成 1 组号码");        
        //随机生成五组号码
        function select()
        {
            val = document.getElementById("zushu").value;            
            var des = "生成 " + val + " 组号码";
            document.getElementById("fiveNumber").setAttribute("title",des);
            document.getElementById("fiveNumber").setAttribute("value",des);
        }        //随机生成五组号码
        function number()
        {            for(var n=1;n<11;n++){                
        for(var m=1;m<8;m++){                    
        var a = "span" + n + m;
                    document.getElementById(a).innerText = "";//每次点击按钮先清空上一次数据                    
                    document.getElementById(a).style.backgroundColor = "white";
                }
            }            for(var x=1;x<(parseInt(val)+1);x++){                //从35个号码里面无放回地取5位
                var arr35 = ["01","02","03","04","05","06","07","08","09","10","11","12","13","14","15","16","17",               
                            "18","19","20","21","22","23","24","25","26","27","28","29","30","31","32","33","34","35"];       
                                     //从12个号码里面无放回地取2位
                var arr12 = ["01","02","03","04","05","06","07","08","09","10","11","12"];                
                var span = "";                
                var temp = "";                
                for(var i=1;i<6;i++){
                    span = "span" + x + i;
                    temp = Math.floor(Math.random()*arr35.length);//随机取一个数                    
                    document.getElementById(span).innerText = arr35[temp];
                    document.getElementById(span).style.backgroundColor = "red";
                    arr35.splice(temp,1);//删除该位置的值                
                    }                
                    for(var j=6;j<8;j++){
                    span = "span" + x + j;
                    temp = Math.floor(Math.random()*arr12.length);//随机取一个数                    
                    document.getElementById(span).innerText = arr12[temp];
                    document.getElementById(span).style.backgroundColor = "blue";
                    arr12.splice(temp,1);//删除该位置的值                
                    }
            }            
            for(var x=1;x<(parseInt(val)+1);x++){                
            var span = "";                //前五位排序
                var arr = new Array(5);                
                for(var y=0;y<5;y++){
                    span = "span" + x + (y+1);
                    arr[y] = document.getElementById(span).lastChild.nodeValue;
                }                var a = bubbleSort(arr);                
                for(var l=0;l<5;l++){
                    span = "span" + (x+5) + (l+1);
                    document.getElementById(span).innerText = a[l];
                    document.getElementById(span).style.backgroundColor = "red";
                }                //后两位排序
                var spann6 = "span" + x + "6";                
                var spann7 = "span" + x + "7";                
                var spanm6 = "span" + (x+5) + "6";                
                var spanm7 = "span" + (x+5) + "7";                
                var span6 = document.getElementById(spann6).lastChild.nodeValue;                
                var span7 = document.getElementById(spann7).lastChild.nodeValue;                
                if(parseInt(span6) > parseInt(span7)){
                    document.getElementById(spanm6).innerText = span7;
                    document.getElementById(spanm7).innerText = span6;
                }else{
                    document.getElementById(spanm6).innerText = span6;
                    document.getElementById(spanm7).innerText = span7;
                }
                document.getElementById(spanm6).style.backgroundColor = "blue";
                document.getElementById(spanm7).style.backgroundColor = "blue";
            }
        }        //插入排序
        function bubbleSort(array){            
        var len = array.length;            
        for (var i = 0; i < len; i++) {                
        for (var j = i; j > 0 && array[j]<array[j-1]; j--) {                       
        var swap = array[j];  //第二个for循环使元素比较并移动到合适位置                       
        array[j] = array[j-1];
                       
                   array[j-1] = swap;
                }
            }            return array;
        }    </script></body></html>

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