终于解决了IE8不支持数组的indexOf方法，array的IndexOf方法

 

/*
终于解决了IE8不支持数组的indexOf方法
*/

if (!Array.prototype.indexOf) {
    Array.prototype.indexOf = function (elt /*, from*/) {
        var len = this.length >>> 0;

        var from = Number(arguments[1]) || 0;
        from = (from < 0)
         ? Math.ceil(from)
         : Math.floor(from);
        if (from < 0)
            from += len;

        for (; from < len; from++) {
            if (from in this &&
          this[from] === elt)
                return from;
        }
        return -1;
    };
}