javascript中，实现的string的format函数

//V1 method
String.prototype.format = function() {
var args = arguments;
return this.replace(/\{(\d+)\}/g, function(m, i){
return args[i];
});
}

//V2 static
String.format = function() {
if( arguments.length == 0 )
return null;

var str = arguments[0];
for(var i=1;i<arguments.length;i++) {
var re = new RegExp('\\{' + (i-1) + '\\}','gm');
str = str.replace(re, arguments[i]);
}
return str;
}

var a = "I Love {0}, and You Love {1},Where are {0}! {4}";
alert(String.format(a, "You","Me"));

alert(a.format("You","Me"));