<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>无标题文档</title>
<script>
/*var str = 'aaaaaaaasddfggdkfhndfre';
*indexOf('s')为数组编写该方法;indexOf('img/1.jpg');
*/
window.onload = function(){
var arrImg = ['img/1.jpg','img/2.jpg','img/3.jpg','img/4.jpg','img/5.jpg','img/3.jpg'];
var arr = [1,2,3,4,5,6,2];
/*由于IE8,不支持数组的indexOf*/
if (!Array.prototype.indexOf){
Array.prototype.indexOf = function(elt){
var len = this.length >>> 0;
var from = Number(arguments[1] || 0);
from = (from < 0)
? Math.ceil(from)
: Math.floor(from);
if (from < 0)
from = 0;//如果第二个参数为负数，则按照0计算
for (; from < len; from++)
{
if (this[from] === elt) //没有必要用from in this 做越界检查
return from;
}
return -1;
};
}
alert(arr.indexOf(2,2));
alert(arrImg.indexOf('img/3.jpg',2));
};
</script>
</head>
<body>
</body>
</html>
