扩展js,实现c#中的string.format方便拼接字符串

//"{0}-{1}-{2}".format("xx","yy","zz")
//显示xx-yy-zz
String.prototype.format = function() {
    var result=this;
    if (arguments.length == 0)
        return null;
    for ( var i = 0; i < arguments.length; i++) {
        var re = new RegExp('\\{' + (i) + '\\}', 'gm');
        result = result.replace(re, arguments[i]);
    }
    return result;
};