function parseQuery(queryString) {
var query = {};
var pairs = (queryString[0] === '?' ? queryString.substr(1) : queryString).split('&');
for (var i = 0; i < pairs.length; i++) {
var pair = pairs[i].split('=');
query[decodeURIComponent(pair[0])] = decodeURIComponent(pair[1] || '');
}
return query;
}
Turns query string like hello=1&another=2 into object {hello: 1, another: 2}. From there, it's easy to extract the variable you need.
That said, it does not deal with array cases such as "hello=1&hello=2&hello=3". To work with this, you must check whether a property of the object you make exists before adding to it, and turn the value of it into an array, pushing any additional bits.
