Read URL GET variable (Javascript)

gistfile1.js

// Given a query string "?to=email&why=because&first=John&Last=smith"
// getUrlVar("to")  will return "email"
// getUrlVar("last") will return "smith"
// 'unescape' is now deprecated for security reasons, so it is replaced here by decodeURIComponent
// MDN proof: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/unescape

// Slightly more concise and improved version based on http://www.jquery4u.com/snippets/url-parameters-jquery/
function getUrlVar(key){
	var result = new RegExp(key + '=([^&]*)', 'i').exec(window.location.search);
	return result && decodeURIComponent( result[ 1 ] ) || '';
}

// To convert it to a jQuery plug-in, you could try something like this:
(function($){
	$.getUrlVar = function(key){
		var result = new RegExp(key + '=([^&]*)', 'i').exec(window.location.search);
		return result && decodeURIComponent( result[ 1 ] ) || ''; 
	};
})(jQuery);