//去除字符串头尾空格或指定字符String.prototype.Trim= function(c){    if(c==null||c=="")    {        var str= this.replace(/^/s*/, '');        var rg = //s/;        var i = str.length;        while (rg.test(str.charAt(--i)));        return str.slice(0, i + 1);    }    else    {        var rg=new RegExp("^"+c+"*");        var str= this.replace(rg, '');        rg = new RegExp(c);        var i = str.length;        while (rg.test(str.charAt(--i)));        return str.slice(0, i + 1);    }}//去除字符串头部空格或指定字符String.prototype.TrimStart = function(c){    if(c==null||c=="")    {        var str= this.replace(/^/s*/, '');        return str;    }    else    {        var rg=new RegExp("^"+c+"*");        var str= this.replace(rg, '');        return str;    }}//去除字符串尾部空格或指定字符String.prototype.trimEnd = function(c){    if(c==null||c=="")    {        var str= this;        var rg = //s/;        var i = str.length;        while (rg.test(str.charAt(--i)));        return str.slice(0, i + 1);    }    else    {        var str= this;        var rg = new RegExp(c);        var i = str.length;        while (rg.test(str.charAt(--i)));        return str.slice(0, i + 1);    }}

来源 http://blog.csdn.net/lyzyjoyo/article/details/6292207