It is worth noting, the library that John Slegers mentioned does have a jQuery dependency, however here is a version that is vanilla Javascript.
https://github.com/EldonMcGuinness/querystring.js
I would have simply commented on his post, but I lack the reputation to do so. :/
The example below process the following, albeit irregular, query string:
?foo=bar&foo=boo&roo=bar;bee=bop;=ghost;=ghost2;&;checkbox%5B%5D=b1;checkbox%5B%5D=b2;dd=;http=http%3A%2F%2Fw3schools.com%2Fmy%20test.asp%3Fname%3Dst%C3%A5le%26car%3Dsaab&http=http%3A%2F%2Fw3schools2.com%2Fmy%20test.asp%3Fname%3Dst%C3%A5le%26car%3Dsaab
var qs = "?foo=bar&foo=boo&roo=bar;bee=bop;=ghost;=ghost2;&;checkbox%5B%5D=b1;checkbox%5B%5D=b2;dd=;http=http%3A%2F%2Fw3schools.com%2Fmy%20test.asp%3Fname%3Dst%C3%A5le%26car%3Dsaab&http=http%3A%2F%2Fw3schools2.com%2Fmy%20test.asp%3Fname%3Dst%C3%A5le%26car%3Dsaab";_x000D_
//var qs = "?=&=";_x000D_
//var qs = ""_x000D_
_x000D_
var results = querystring(qs);_x000D_
_x000D_
(document.getElementById("results")).innerHTML =JSON.stringify(results, null, 2);
_x000D_
<script _x000D_
src="https://rawgit.com/EldonMcGuinness/querystring.js/master/dist/querystring.min.js"></script>_x000D_
<pre id="results">RESULTS: Waiting...</pre>
_x000D_