This is a simple jQuery plugin that lets you grab the url parameter value and append it to any input you'd like.

grabbit.js

// This is a simple jQuery plugin that lets you grab the url parameter value and append it to any input you'd like .
//
// Example: 
// Your url is : http://myurl.com/?name=Jerry&last=Lopez&age=21
//
// Now lets say you have a form that you want prefilled when a user visit the form. You can
// can accomplish that with grabbit it will pull the name, last and age parameters then add
// them to the input fields you specify.
//
// Usage:
// $("input.name").grabbit('name');
// $("input.last").grabbit('last');
// $("input.age").grabbit('age');
(function ( $ ) {
 
	$.fn.grabbit = function( urlParam ){
		function getParameterByName(name) {
    		name = name.replace(/[\[]/, "\\[").replace(/[\]]/, "\\]");
    		var regex = new RegExp("[\\?&]" + name + "=([^&#]*)"),
    		results = regex.exec(location.search);
    		
    		return results == null ? "" : decodeURIComponent(results[1].replace(/\+/g, " "));
		}

		return this.val(getParameterByName(urlParam));
	};
 
}( jQuery ));