1.for循环

for(......){
.........;
}

实例：

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>cycle</title>
<script type="text/javascript">

/*var aList01 = ['a','b','c','d'];var aLen = aList01.length;for(var i=0;i<aLen;i++){ alert(aList01[i]);}*/window.onload = function(){ var oUl = document.getElementById('ul'); var aList = ['美人鱼','大黄蜂','变形金刚','海王']; var sTr = ''; for(var i=0;i<aList.length;i++){ sTr += '<li>' + aList[i] + '</li>'; } /*alert(sTr);*/ oUl.innerHTML = sTr;}</script>

<style type="text/css">

.ulcon{ width: 300px; height: 300px; list-style: none; margin: 50px auto 0;}.ulcon li{ height: 70px; line-height: 70px; border-bottom: 1px dotted #000;}</style>

</head>

<body>

<ul class="ulcon" id="ul"> <!--<li>美人鱼</li> <li>美人鱼</li> <li>美人鱼</li> <li>美人鱼</li>--></ul>

</body>
</html>

2.while循环

var ....
while(....){
.......
i++;
}

3.数组去重

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>repea</title>
<script type="text/javascript">

var aList01 = [1,2,4,5,5,8,4,7,8,4,6,1,9,5,4,9];var iLen = aList01.length;var aList02 = [];for(var i=0;i<iLen;i++){ if(aList01.indexOf(aList01[i])==i){ /*每个重复数字的位置是第一个*/ aList02.push(aList01[i]); }}alert(aList02);</script>

</head>

<body>
</body>
</html>