The code
This Gist by Eldon McGuinness is by far the most complete implementation of a JavaScript query string parser that I've seen so far.
Unfortunately, it's written as a jQuery plugin.
I rewrote it to vanilla JS and made a few improvements :
function parseQuery(str) {
var qso = {};
var qs = (str || document.location.search);
// Check for an empty querystring
if (qs == "") {
return qso;
}
// Normalize the querystring
qs = qs.replace(/(^\?)/, '').replace(/;/g, '&');
while (qs.indexOf("&&") != -1) {
qs = qs.replace(/&&/g, '&');
}
qs = qs.replace(/([\&]+$)/, '');
// Break the querystring into parts
qs = qs.split("&");
// Build the querystring object
for (var i = 0; i < qs.length; i++) {
var qi = qs[i].split("=");
qi = qi.map(function(n) {
return decodeURIComponent(n)
});
if (typeof qi[1] === "undefined") {
qi[1] = null;
}
if (typeof qso[qi[0]] !== "undefined") {
// If a key already exists then make this an object
if (typeof (qso[qi[0]]) == "string") {
var temp = qso[qi[0]];
if (qi[1] == "") {
qi[1] = null;
}
qso[qi[0]] = [];
qso[qi[0]].push(temp);
qso[qi[0]].push(qi[1]);
} else if (typeof (qso[qi[0]]) == "object") {
if (qi[1] == "") {
qi[1] = null;
}
qso[qi[0]].push(qi[1]);
}
} else {
// If no key exists just set it as a string
if (qi[1] == "") {
qi[1] = null;
}
qso[qi[0]] = qi[1];
}
}
return qso;
}
How to use it
var results = parseQuery("?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");
Output
{
"foo": ["bar", "boo" ],
"roo": "bar",
"bee": "bop",
"": ["ghost", "ghost2"],
"checkbox[]": ["b1", "b2"],
"dd": null,
"http": [
"http://w3schools.com/my test.asp?name=ståle&car=saab",
"http://w3schools2.com/my test.asp?name=ståle&car=saab"
]
}
See also this Fiddle.
