JavaScript原生对象的api有些情况下使用并不方便，考虑扩展基于Object、Function、String、Array扩展，参考了prototype.js的部分实现，做了提取和修改，分享下：

/** * * @authors yinshen (shenyin19861216@163.com) * @date        2013-09-05 23:23:25 * @version $Id$ *///Object 扩展(function() {    var FUNCTION_CLASS = '[object Function]',        BOOLEAN_CLASS = '[object Boolean]',        NUMBER_CLASS = '[object Number]',        STRING_CLASS = '[object String]',        ARRAY_CLASS = '[object Array]',        OBJECT_CLASS = '[object Object]',        DATE_CLASS = '[object Date]';    function extend(destination, source) {        for (var property in source) {            destination[property] = source[property];        }        return destination;    }    function clone(o,deep) {        if (deep === true) {            var target = {};            for (var property in o) {                if (o.hasOwnProperty(property)) {                    if (Object.isObject(o[property])) {                        target[property] = Object.clone(o[property],true);                    } else {                        target[property] = o[property];                    }                }            }            return target;        } else {            return extend({}, o);        }    }    function isElement(object) {        return !!(this && object.nodeType == 1);    }    function isObject(object) {        return Object.prototype.toString.call(object) === OBJECT_CLASS;    }    function isArray(object) {        return Object.prototype.toString.call(object) === ARRAY_CLASS;    }    function isFunction(object) {        return Object.prototype.toString.call(object) === FUNCTION_CLASS;    }    function isString(object) {        return Object.prototype.toString.call(object) === STRING_CLASS;    }    function isNumber(object) {        return Object.prototype.toString.call(object) === NUMBER_CLASS;    }    function isDate(object) {        return Object.prototype.toString.call(object) === DATE_CLASS;    }    function isUndefined(object) {        return typeof object === "undefined";    }    function param(object) {        var arr = [];        for (var prop in object) {            if (object.hasOwnProperty(prop)) {                arr.push([encodeURIComponent(prop), "=", encodeURIComponent(object[prop]), "&"].join(""));            }        }        return arr.join("").slice(0, -1);    }    function each(object,fn) {        if(typeof fn ==="undefined"){
   return;}        for (var prop in object) {            if (object.hasOwnProperty(prop)) {                if (fn(object[prop], prop) === false) {                    break;                }            }        }    }    extend(Object, {    //extend(Object.prototype, {
            extend: extend,        clone: clone,        isObject: isObject,        isElement: isElement,        isArray: isArray,        isFunction: isFunction,        isString: isString,        isNumber: isNumber,        isDate: isDate,        isUndefined: isUndefined,        param: param,        each: each    });})();//String 扩展Object.extend(String.prototype, (function() {    //字符串替换，支持{}和[]    function format(o) {        return this.replace(/\{(\w+)\}/g, function($1, $2) {            return o[$2] !== undefined ? o[$2] : $1;        });    };    //获取字符串长度，区分中文占2个字符    function len() {        return this.replace(/[^\x00-\xff]/g, '**').length;    }    function truncate(length, truncation) {        length = length || 30;        truncation = Object.isUndefined(truncation) ? '...' : truncation;        return this.length > length ?            this.slice(0, length - truncation.length) + truncation : String(this);    }    function trim(isLeft) {        if (isLeft === true) {            return this.replace(/^\s+/, '');        } else if (isLeft === false) {            return this.replace(/\s+$/, '');        }        return this.replace(/^\s+/, '').replace(/\s+$/, '');    }    var htmlDiv=document.createElement("div");    function html(escape) {/*        var replace = ["'", "'", '"', """, " ", " ", ">", ">", "<", "<", "&", "&", ];        escape === false && replace.reverse();        for (var i = 0, str = this; i < replace.length; i += 2) {            str = str.replace(new RegExp(replace[i], 'g'), replace[i + 1]);        }        return str;*/        function encode(){            htmlDiv.innerHTML="";            return htmlDiv.appendChild(document.createTextNode(this)).parentNode.innerHTML.replace(/\s/g, " ");        }        function decode(){            htmlDiv.innerHTML=this;            return htmlDiv.innerText;        }                var str=this;        return escape===false?decode.apply(str):encode.apply(str);    }    function has(pattern) {        return this.indexOf(pattern) > -1;    }    function startsWith(pattern) {        return this.lastIndexOf(pattern, 0) === 0;    }    function endsWith(pattern) {        var d = this.length - pattern.length;        return d >= 0 && this.indexOf(pattern, d) === d;    }    function empty() {        return this == '';    }    function text() {        return this.replace(/<\/?[^>]*\/?>/g, '');    }    function blank() {        return /^\s*$/.test(this);    }    function sprintf(){        var             i,                          result = this,            param,            reg,            length = arguments.length;        if (length < 1){            return text;        }                i = 0;        while(i < length){            result = result.replace(/%s/, '{#' + (i++) + '#}');                         }        result.replace('%s', '');                 i = 0;        while( (param = arguments[i])!==undefined ){ // 0 也是可能的替换数字            reg = new RegExp('{#' + i + '#}', 'g')            result = result.replace(reg, param);            i++;        }        return result;    }    function bytes() {        var str = this,            i = 0,            _char,            l = 0;        while(_char = str.charAt(i++)){            l += (_char).charCodeAt().toString(16).length / 2;        }        return l;    }    return {        format: format,        sprintf:sprintf,        text: text,        len: len,        truncate: truncate,        trim: String.prototype.trim || trim,        html: html, //"&<>".html()==="&<>"    "&<>".html(false)==="&<>"        has: has,        startsWith: startsWith,        endsWith: endsWith,        empty: empty, //内容为空，连空格都没                        "     ".empty()===false        blank: blank, //没有任何有意义的字符，空格不算    "     ".blank()===true        bytes : bytes //计算一个字符串的字节长度    };})());//Function 扩展Object.extend(Function.prototype, (function() {    var slice = Array.prototype.slice;    function update(array, args) {        var arrayLength = array.length,            length = args.length;        while (length--) array[arrayLength + length] = args[length];        return array;    }    function merge(array, args) {        array = slice.call(array, 0);        return update(array, args);    }    function bind(context) {        if (arguments.length < 2 && Object.isUndefined(arguments[0])) return this;        var __method = this,            args = slice.call(arguments, 1);        return function() {            var a = merge(args, arguments);            return __method.apply(context, a);        }    }    /*        这东西炫耀的价值大于实用，还是不引入了    function curry() {        if (!arguments.length) return this;        var __method = this, args = slice.call(arguments, 0);        return function() {            var a = merge(args, arguments);            return __method.apply(this, a);        }    }    function uncurry(){            var __method=this;            return function(){                    Function.prototype.call.apply(__method,arguments);            }    }*/    function delay(timeout) {        var __method = this,            args = slice.call(arguments, 1);        timeout = timeout * 1000;        return window.setTimeout(function() {            return __method.apply(__method, args);        }, timeout);    }    function defer() {        var args = update([0.01], arguments);        return this.delay.apply(this, args);    }    function before(fn) {        var __method = this;        return function() {            if (fn.apply(this, arguments) === false) {                return false;            }            return __method.apply(this, arguments);        }    }    function after(fn) {        var __method = this;        return function() {            var ret = __method.apply(this, arguments);            var args = update([ret], arguments);            fn.apply(this, args);            return ret;        }    }    function wrap(wrapper) {        var __method = this;        return function() {            var a = update([__method.bind(this)], arguments);            return wrapper.apply(this, a);        }    }    return {        bind: bind,        delay: delay,        defer: defer,        before: before,        after: after,        wrap: wrap    }})());//Array扩展(function() {    var arrayProto = Array.prototype,        slice = arrayProto.slice;    function each(iterator, context) {        for (var i = 0, length = this.length >>> 0; i < length; i++) {            if (i in this) iterator.call(context, this[i], i, this);        }    }    function last() {        return this[this.length - 1];    }    function clone(deep) {        if (deep === true) {            return Object.clone.apply(this, arguments);        }        return slice.call(this, 0);    }    function map(fn) {        var arr = [];        this.each(function(v, k) {            arr.push( fn(v, k) );        });        return arr;    }    Object.extend(arrayProto, {        each: Array.prototype.forEach || each,        last: last,        clone: clone,        map: map    });})();