jQuery implementation of widescreen image carousel tutorial_jquery

This article describes an example tutorial of implementing widescreen image carousel with jQuery. Share it with everyone for your reference. The details are as follows:
The screenshot of the running effect is as follows:

Introduce jquery library

<script src="js/jquery-1.9.1.min.js" type="text/javascript"></script>

Build html
The entire code is divided into three parts:

1. Loading part;

2. In the picture part, there can only be 4 pictures here. Friends who are interested can improve it;

3. The TAB button part. Of course, there are only 4 buttons here, and they also need to be improved.

<div class="gg" id="gg">
      <div class="ggLoading">
        <div class="ggLoading2"><em>精彩活动载入中</em></div>
      </div>
      <div class="ggs">
        <div class="ggBox" id="ggBox">
          <a href="#" title="5月22日测试开启领报名资格" style="z-index: 3; opacity: 4;">
            <img src="images/1.jpg" alt="" /></a>
          <a href="#" title="首测世界的雕琢篇章开启">
            <img src="images/2.jpg" alt="" /></a>
          <a href="#" title="上古世纪游戏资料手册">
            <img src="images/3.jpg" alt="" /></a>
          <a href="#" title="游戏四大特色揭晓">
            <img src="images/4.jpg" alt="" /></a>
        </div>
      </div>
      <div class="ggb">
        <div class="ggBtns" id="ggBtns">
          <a title="5月22日测试开启领报名资格" href='javascript:void(0)' class="ggOn"><em>5月22日测试开启领报名资格</em></a>
          <a title="首测世界的雕琢篇章开启" href='javascript:void(0)'><em>首测世界的雕琢篇章开启</em></a>
          <a title="上古世纪游戏资料手册" href='javascript:void(0)'><em>上古世纪游戏资料手册</em></a>
          <a title="游戏四大特色揭晓" href='javascript:void(0)'><em>游戏四大特色揭晓</em></a>
        </div>
      </div>
    </div>

CSS style
The CSS here can be customized according to project needs. You don’t have to stick to the code below, as long as you understand the principles. If you don’t understand the CSS below, just make up for it. I won’t explain it one by one here.

.ggLoading, .ggLoading2 {
  background-image: url(../images/nav.png);
}
.gg {
  width: 100%;
  height: 500px;
  position: relative;
  z-index: 1;
  overflow: hidden;
  margin: 0 auto;
  background: #d3d3d3 url(../images/loading.jpg) repeat-x;
}
.ggLoading {
  position: absolute;
  left: 40%;
  top: 200px;
  width: 325px;
  text-align: center;
  height: 56px;
  background-position: 0 -274px;
  background-repeat: no-repeat;
  line-height: 56px;
  color: #9c9c9c;
}
.ggLoading2 {
  width: 330px;
  height: 56px;
  background-position: 213px -330px;
  background-repeat: no-repeat;
}
.ggLoading em {
  font-weight: bold;
}
.ggs {
  width: 200%;
  height: 500px;
  left: -50%;
  top: 0;
  position: absolute;
}
.ggBox {
  width: 1920px;
  height: 500px;
  margin: 0 auto;
}
.ggBox a {
  display: block;
  width: 1920px;
  height: 500px;
  position: absolute;
  z-index: 1;
  opacity: 0.1;
}
.ggBox img {
  display: block;
  width: 1920px;
  height: 500px;
}
.ggb {
  position: absolute;
  width: 100%;
  left: 0;
  bottom: 0;
  height: 40px;
  z-index: 4;
  background-color: #32342e;
  background-repeat: repeat-x;
  background-position: 50% -40px;
}
.ggBtns {
  width: 960px;
  height: 40px;
  margin: 0 auto;
  border-left: 1px solid #090908;
  border-right: 1px solid #6a6a60;
}
.ggBtns a {
  float: left;
  display: block;
  width: 240px;
  height: 40px;
  text-align: center;
  padding-top: 10px;
  color: #848380;
  font-size: 14px;
  line-height: 40px;
  background-position: 0 10px;
  position: relative;
  top: -10px;
  outline: none;
  background-repeat: no-repeat;
  cursor: pointer;
}
.ggBtns a em {
  display: block;
  width: 210px;
  height: 40px;
  margin: 0 auto;
  overflow: hidden;
}
.ggBtns a:hover {
  color: #e7e7e7;
}
.ggBtns a:focus {
  outline: none;
}
.ggBtns a.ggOn {
  color: #e7e7e7;
  background-position: 0 0;
}
.ggb, .ggBtns a {
  background-image: url(../images/main.jpg);
}
a.ggOn {
  background-image: url(../images/gg.png);
}

JS code
Finally, we have come to the important part. There is not much code in this part, so let’s take a look at it.

$(function () {//文档加载后执行
   
  //定义$con,$box,$btns,$i变量，autoChange自动播放函数，loop定时器。 
  var $con = $('#gg'), $box = $con.find('#ggBox'), $btns = $con.find('#ggBtns'), i = 0, autoChange = function () {
    i += 1;//计数器+1
    if (i === 4) { i = 0; }//如果计数器i等4就把i重置为0.
     
    $btns.find('a:eq(' + i + ')').addClass('ggOn').siblings().removeClass('ggOn');
    //找到TAB按钮中的第i个a标签，为其加上ggOn的样式，同时移除所有同级的a标签ggOn样式
    var curr = $box.find('a:eq(' + i + ')'), prev = curr.siblings();
    //定义curr变量，并赋值为$box中当前显示图片的a标签，定义prev变量，赋值为$box中除了当前显示图片的A标签外的所有A标签。
    prev.css('z-index', 2);//$box中除了当前显示图片的A标签外的所有A标签的index值变为2，即向下移一层
    curr.css('z-index', 3).animate({ //$box中当前显示图片的a标签index值变为3，即向上移一层，然后使用jquery动画以150毫秒把透明度变为1，之后执行匿名函数function。
      'opacity': 1
    }, 150, function () { //$box中除了当前显示图片的A标签外的所有A标签的index值变为1，并把透明度变为0.1
      prev.css({
        'z-index': 1, 'opacity': 0.1
      });
    });
  }, loop = setInterval(autoChange, 5000);//定义定时器，每5秒执行一次autoChange函数，达到自动播放效果。
  $con.hover(function () { //定义鼠标悬浮与离开事件
    clearInterval(loop); //鼠标悬浮时移除Loog定时器，即停止播放
  }, function () {
    loop = setInterval(autoChange, 5000); //鼠标离开时载放Loog定时器，继续播放
  });
  $btns.find('a').click(function () {//定义tab按钮事件
    i = $(this).index() - 1; //tab按钮中当前A标签的index值-1，并赋值给i计数器
    autoChange();  //调用切换方法切换图片
  });
});

I wonder if you guys understand the principle after reading the above notes? In fact, the entire code is divided into four parts:
1. Image switching
Use i as the counter, display the picture currently for i, hide all other pictures, add the ggOn style to the button currently for i, remove the ggOn style for other buttons, and i will increment each time the switching function is called 1.
2. Automatic play
Define a timer loop to call the switching function every 5 seconds.
3. Mouse hover event
It turns out that the loop timer is cleared when the mouse is hovering, and the loop timer is loaded when the mouse leaves.
4. Button event
Bind the tab button click event. After clicking, assign i the index value of the current tab button -1, and call the switching function.

The above is all the key code for jquery to implement image carousel. I hope you will study it carefully. There are still many shortcomings in the tutorial and I hope you can improve it.