read query parameter values from current URL in JavaScript

window_location_param.js

window.location.param = function(key) {
  var value;
	window.location.search.slice(1).split('&').map(function(e) {
		e = decodeURIComponent(e);
		if (e.indexOf(key + '=') === 0) {
			value = e.slice(key.length + 1);
			return false;
		}
	});
	return value;
};

// ?id=123&ws=abc&ls=xyz
window.location.param('id'); // '123'
window.location.param('ls'); // 'xyz'