$.extend(String.prototype,{
        isPositiveInteger: function() {
            return (new RegExp(/^[1-9]\d*$/).test(this))
        },isInteger: function() {
            return (new RegExp(/^\d+$/).test(this))
        },isNumber: function() {
            return (new RegExp(/^([-]{0,1}(\d+)[\.]+(\d+))|([-]{0,1}(\d+))$/).test(this))
        },includeChinese: function() {
        	return (new RegExp(/[\u4E00-\u9FA5]/).test(this))
        },trim: function() {
            return this.replace(/(^\s*)|(\s*$)|\r|\n/g,'')
        },startsWith: function (pattern) {
            return this.indexOf(pattern) === 0
        },endsWith: function(pattern) {
            var d = this.length - pattern.length
            return d >= 0 && this.lastIndexOf(pattern) === d
        },replaceSuffix: function(index) {
            return this.replace(/\[[0-9]+\]/,'['+index+']').replace('#index#',index)
        },replaceSuffix2: function(index) {
            return this.replace(/\-(i)([0-9]+)$/,'-i'+ index).replace('#index#',trans: function() {
            return this.replace(/&lt;/g,'<').replace(/&gt;/g,'>').replace(/&quot;/g,'"')
        },encodeTXT: function() {
            return (this).replaceAll('&','&amp;').replaceAll('<','&lt;').replaceAll('>','&gt;').replaceAll(' ','&nbsp;')
        },replaceAll: function(os,ns) {
            return this.replace(new RegExp(os,'gm'),ns)
        },/*替换占位符为对应选择器的值*/ //{^(.|\#)[A-Za-z0-9_-\s]*}
        replacePlh: function($Box) {
            $Box = $Box || $(document)
            return this.replace(/{\/?[^}]*}/g,function($1) {
                var $input = $Box.find($1.replace(/[{}]+/g,''))
                
                return $input && $input.val() ? $input.val() : $1
            })
        },replaceMsg: function(holder) {
            return this.replace(new RegExp('({.*})','g'),holder)
        },replaceTm: function($data) {
            if (!$data) return this
            
            return this.replace(RegExp('({[A-Za-z_]+[A-Za-z0-9_-]*})',function($1) {
                return $data[$1.replace(/[{}]+/g,'')]
            })
        },replaceTmById: function(_Box) {
            var $parent = _Box || $(document)
            
            return this.replace(RegExp('({[A-Za-z_]+[A-Za-z0-9_-]*})',function($1) {
                var $input = $parent.find('#'+ $1.replace(/[{}]+/g,''))
                return $input.val() ? $input.val() : $1
            })
        },isFinishedTm: function() {
            return !(new RegExp('{\/?[^}]*}').test(this))
        },skipChar: function(ch) {
            if (!this || this.length===0) return ''
            if (this.charAt(0)===ch) return this.substring(1).skipChar(ch)
            return this
        },isValidPwd: function() {
            return (new RegExp(/^([_]|[a-zA-Z0-9]){6,32}$/).test(this))
        },isValidMail: function() {
            return(new RegExp(/^\w+((-\w+)|(\.\w+))*\@[A-Za-z0-9]+((\.|-)[A-Za-z0-9]+)*\.[A-Za-z0-9]+$/).test(this.trim()))
        },isSpaces: function() {
            for (var i = 0; i < this.length; i += 1) {
                var ch = this.charAt(i)
                
                if (ch!=' '&& ch!='\n' && ch!='\t' && ch!='\r') return false
            }
            return true
        },isPhone:function() {
            return (new RegExp(/(^([0-9]{3,4}[-])?\d{3,8}(-\d{1,6})?$)|(^\([0-9]{3,4}\)\d{3,8}(\(\d{1,6}\))?$)|(^\d{3,8}$)/).test(this))
        },isUrl:function() {
            return (new RegExp(/^[a-zA-z]+:\/\/([a-zA-Z0-9\-\.]+)([-\w .\/?%&=:]*)$/).test(this))
        },isExternalUrl:function() {
            return this.isUrl() && this.indexOf('://'+ document.domain) == -1
        });

JS 继承讲解模块连接

http://www.cnblogs.com/sanshi/archive/2009/07/08/1519036.html