String.prototype.format = function() {
var a = arguments;
return this.replace(/\{\d+\}/g, function(c){
return a[c.match(/\d+/)];
});
}
// usage:
var str = 'Hello, {0}! You are {1}!';
str.format('friend', 'awesome');
// Hello, friend! You are awesome!
P.S.: Вот как-то так :D