A tiny templating technique by extending the String prototype in JavaScript

gistfile1.txt

String.prototype.format = function(){
    var args = arguments;
    obj = (args.length == 1 && (typeof args[0] == 'object')) ? args[0] : args; 
    return this.replace(/\{(\w+)\}/g, function(m, i){
        return obj[i];
    });
}

// Example usage:

// Here is a template string
var templateString = '<div class="item"><h1>{username}</h1><p>{description}</p></div>';

// Here is an example data set, a list of users:
var response = [{username:'fil',description:'awesome'},{username:'steve',description:'not so awesome'}];

// Interpolate into the template string
response.forEach(function(user) {
    document.write(templateString.format({
        username:user.username,
        description:user.description
    });
});