js array 取指定元素索引、判断是否相同、重复、过滤数据

 
最近写js也多了，Array中有好多方法不够用。自己加了些以后还可能用到。  

<script type="text/javascript">          
        //找到返回所在索引，不存在返回-1   
        Array.prototype.index = function (el) {   
            var i = 0;   
            for (var i = 0, len = this.length; i < len; i++) {   
                if (el == this[i]) {   
                    return i;   
                }   
            }   
            return -1;     
        };   
           
        //是否相同，相同返回true，不同返回false                                  
        Array.prototype.same = function () {      
            if (this.length == 0) {   
                return true;   
            }   
            var temp = this.join('').replaceAll(this[0], "");      
            if (temp != "") {      
                return false;      
            } else {      
                return true     
            }      
        };                 
        //replaceAll函数参考：http://blog.csdn.net/IBM_hoojo/archive/2010/06/17/5675096.aspx            
  
        //判断是否存在重复数据   
        Array.prototype.iterate = function () {   
            var flag = false;   
            for (var i = 0, len = this.length; i < len; i++) {   
                for (var j = 0; j < len; j++) {   
                    if (this[i] == this[j] && i != j) {   
                        flag = true;   
                        break;   
                    }   
                }   
            }   
            return flag;   
        };   
           
        //传入一个回调，根据回调函数条件过滤数组   
        Array.prototype.filter = function(callback) {   
            var rs = [];       
            for ( var i = 0, length = this.length; i < length; i++ ) {   
                if (callback(this[i], i)) {   
                    rs.push(this[i]);   
                }   
            }   
            return rs;   
        };   
           
        window.onload = function () {   
            var ary = [1, 2, 3, 4, 6, 4, 5];   
            alert(ary.index(6));   
            alert(ary.same());   
            alert(ary.iterate());   
            var a = ary.filter(function (n, i) {   
                return n > 4;   
            });   
               
            alert(a.length + "-" + a[0]);   
        }   
    </script>  

本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/IBM_hoojo/archive/2010/06/17/5675195.aspx