JavaScript1.6数组新特性介绍以及JQuery的几个工具方法

var ary = [2,4,6,8];

// js1.6 Array.forEach方法
ary.forEach(function(i){alert(i);});

// jquery的写法
$(ary).each(function(){alert(this);});
//还可以写成这样
$(ary).each(function(index,item){alert(item);});//index是元素的索引，item是该元素

var ary = [2,4,6,8];

// js1.6 Array.filter()方法
var otherAry1 = ary.filter(function(item){return item>4;});
alert(otherAry1);//输出6，8

// jquery写法(注意和$.each的区别)
// 此处函数中第一个参数是数组元素自身，第二个参数是数组元素索引
// 而$().each方法刚好相反，作者应该统一下。
var otherAry2 = $.grep(ary,function(item,index){
     return item>4;
});
alert(otherAry2);//输出6，8

var ary = [2,4,6,8];

// js1.6 Array.map()方法
var newAry1 = ary.map(function(item){return item+1;});//每个元素加1
alert(newAry1);//输出3，5，7，9

// jquery写法
var newAry2 = $.map(ary,function(item,index){return item+1;});
alert(newAry2);//输出3，5，7，9

var ary = [2,4,6,8,10];

alert(ary.every(function(item){return item>1}));//true
alert(ary.every(function(item){return item>2}));//false

var ary = [2,4,,6,8,10];

alert(ary.some(function(item){return item>9;}));//true
alert(ary.some(function(item){return item>10;}));//false

-function(){

function applyIf(o, c) {
    if(o) {
        for(var p in c) {
            if(o[p]===undefined) {
                o[p] = c[p];
            }
        }
    }
    return o;
}
applyIf(Array.prototype, {
    indexOf : function(obj, idx) {
        var from = idx == null ? 0 : (idx < 0 ? Math.max(0, arr.length + idx) : idx);
        for(var i = from, l = this.length; i < l; i++) {
            if(i in this && this[i] === obj) {
                return i;
            }
        }
        return -1;
    },
    lastIndexOf : function(obj, idx) {
        var len = this.length, from = idx == null ? len - 1 : idx;
        if(from < 0) {
            from = Math.max(0, len + from);
        }
        for(var i = from; i >= 0; i--) {
            if (i in this && this[i] === obj) {
                return i;
            }
        }
        return -1;
    },
    every : function(fn, thisObj) {
        var l = this.length;
        for(var i = 0; i < l; i++) {
            if(i in this && !fn.call(thisObj, this[i], i, this)) {
                return false;
            }
        }
        return true;
    },
    some : function(fn, thisObj) {
        var l = this.length;
        for(var i = 0; i < l; i++) {
            if(i in this && fn.call(thisObj, this[i], i, this)) {
                return true;
            }
        }
        return false;
    },
    filter : function(fn, thisObj) {
        var l = this.length, res = [], resLength = 0;
        for(var i = 0; i < l; i++) {
            if(i in this) {
                var val = this[i];
                if(fn.call(thisObj, val, i, this)) {
                    res[resLength++] = val;
                }
            }
        }
        return res;
    },
    map : function(fn, thisObj) {
        var l = this.length, res = [];
        for(var i = 0; i < l; i++) {
            if(i in this) {
                res[i] = fn.call(thisObj, this[i], i, this);
            }
        }
        return res;
    },
    forEach : function(fn, thisObj) {
        var l = this.length;
        for(var i = 0; i < l; i++) {
            if(i in this) {
                fn.call(thisObj, this[i], i, this);
            }
        }
    }
}); 
}();