crude hack to retrieve query params using javascript. Should be using a closure, and need to have more intelligent and fully working (doesn't work properly with urlencoded names) array handling.

gistfile1.js

function getParam(p) {
	if( typeof getParam.qs == 'undefined' ) {
		getParam.qs = '';
		getParam.params = {};
	}
	if( !window.location.search ) {
		return false;
	}
	if( getParam.qs != window.location.search ) {
		getParam.qs = window.location.search;
		getParam.params = getAllParams(getParam.qs);
	}

	if( !arguments.length || typeof p == 'undefined' ) {
		return getParam.params;
	} else if( p in getParam.params ) {
		return getParam.params[p];
	} else {
		return false;
	}
}

function getAllParams() {
	var e,
		d = function (s) { return decodeURIComponent(s).replace(/\+/g, " "); },
		q = window.location.search.substring(1),
		r = /([^&=]+)=?([^&]*)/g,
		urlParams = {};

	while (e = r.exec(q)) {
		if (e[1].indexOf("[") == "-1")
			urlParams[d(e[1])] = d(e[2]);
		else {
			var b1 = e[1].indexOf("["),
				aN = e[1].slice(b1+1, e[1].indexOf("]", b1)),
				pN = d(e[1].slice(0, b1));

			if (typeof urlParams[pN] != "object")
				urlParams[d(pN)] = {},
				urlParams[d(pN)].length = 0;

			if (aN)
				urlParams[d(pN)][d(aN)] = d(e[2]);
			else
				Array.prototype.push.call(urlParams[d(pN)], d(e[2]));

		}
	}
	return urlParams;
}