Cedric Ruiz

What if there is more than one element with same class? You'd have to use querySelectorAll, and loop, just like getElementsByClassName. For id's I don't think it's even worth using querySelector, no real gains there, id's are unique. A better example where querySelectorAll is really useful, querying selectors:

var els = document.querySelectorAll('ul > li a');

It's useful in some cases. It's just a different pattern where you have a function that can take arguments of many types. For example the jQuery constructor could be done with overloading as it takes an element, an array, a pseudo-array, a jQuery collection, a string, etc... Here's a simple example:

var double = overload({
  String: function(x) {
    return x + x;
  },
  Number: function(x) {
    return x * 2;
  }
});

console.log(double('hey')); //=> heyhey
console.log(double(9)); //=> 18

You can use multiple if statements to check the type and the arguements object to count the arguments, but the typeof operator is not reliable and it'll end up looking ugly and difficult to understand; you'd have to write comments to clarify what you're checking. With overloading you solve this issue.

Here's a more portable/maintainable approach for a jQuery-like library:
https://gist.github.com/elclanrs/5341331

Nice snippet. Here's a shorter version:
String.prototype.template = function() { var args = arguments; return this.replace(/\{([^}]+?)\}/g, function(_, match) { return args[match]; }); };

http://jsbin.com/ojeriz/1/edit

It's probably because console.log is not supported on wp7. You can use a polyfill http://paulirish.com/2009/log-a-lightweight-wrapper-for-consolelog/. Why would you log anything in production anyway?