首页 > 技术文章 > javascript实现ul中列表项随机排列

ifworld 2017-10-17 15:15 原文

方法1

<!DOCTYPE html>
<html lang="en">
<head>
  <script type="text/javascript">
    window.onload=function(){
      var arr = new Array(1,2,3,4,5,6);
      var ul = document.getElementsByTagName('ul')[0];
      var len1 = arr.length;
      var len = len1;
      var index = parseInt(Math.random()*len1);
      for(var i=0;i<len1;i++){
        ul.appendChild(ul.children[index]);
        arr.pop(index);
        len = arr.length;
        index = parseInt(Math.random()*len);
      }
    };
  </script>
 </head> 
 <body>
  <ul>
    <li>苹果</li>
    <li>桔子</li>
    <li>香蕉</li>
    <li>石榴</li>
    <li>桃子</li>
    <li>菠萝</li>
  </ul>
 </body>
</html>

方法2

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<script>
  window.onload = function(){
    var arr = [['<li>1</li>'],['<li>2</li>'],['<li>3</li>'],['<li>4</li>'],['<li>5</li>'],['<li>6</li>']];
    var result = '';
    var len = arr.length;
    for(var i=0;i<len ;i++){
      var rand = parseInt(arr.length*Math.random());
      result += arr[rand];
      arr.splice(rand,1);
    }
    document.getElementsByTagName("ul")[0].innerHTML= result ;
  };
  //arr 数组就是ul里的内容组成的字符串数组
</script>
</head>
<body>
  <ul></ul>
</body>
</html>

方法3

 

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<script type="text/javascript">
  window.onload = function(){
    var ul = document.getElementsByTagName("ul")[0];
    var lis = document.getElementsByTagName("li");
    var arr = [];
    for(var i = 0; i < lis.length; i++){
      arr.push(lis[i]);
    }
    arr.sort(function(a,b){
      /*var rand = Math.random();
      if(rand > 0.5) {
        return 1;
      }else if(rand < 0.5){
        return -1;
      } else {
        return 0;
      }*/
      return Math.random()>.5 ? -1 : 1;
      //通过随机产生0到1的数,然后判断是否大于0.5从而影响排序,产生随机性的效果。
    });
    for(var i = 0; i < arr.length; i++){
      ul.appendChild(arr[i]);
    }
  }
</script>
</head>
<body>
  <ul>
    <li>1</li>
    <li>2</li>
    <li>3</li>
    <li>4</li>
    <li>5</li>
  </ul>
</body>
</html>

 

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