You can extract the key/value pairs from the location.search property, this property has the part of the URL that follows the ? symbol, including the ? symbol.

function getQueryString() {
var result = {}, queryString = location.search.slice(1),
re = /([^&=]+)=([^&]*)/g, m;


while (m = re.exec(queryString)) {
result[decodeURIComponent(m[1])] = decodeURIComponent(m[2]);
}


return result;
}


// ...
var myParam = getQueryString()["myParam"];

Okay, since everyone is ignoring my actual question, heh, I'll post mine too! Here's what I have:

location.querystring = (function() {


// The return is a collection of key/value pairs


var queryStringDictionary = {};


// Gets the query string, starts with '?'


var querystring = unescape(location.search);


// document.location.search is empty if no query string


if (!querystring) {
return {};
}


// Remove the '?' via substring(1)


querystring = querystring.substring(1);


// '&' seperates key/value pairs


var pairs = querystring.split("&");


// Load the key/values of the return collection


for (var i = 0; i < pairs.length; i++) {
var keyValuePair = pairs[i].split("=");
queryStringDictionary[keyValuePair[0]] = keyValuePair[1];
}


// Return the key/value pairs concatenated


queryStringDictionary.toString = function() {


if (queryStringDictionary.length == 0) {
return "";
}


var toString = "?";


for (var key in queryStringDictionary) {
toString += key + "=" + queryStringDictionary[key];
}


return toString;
};


// Return the key/value dictionary


return queryStringDictionary;
})();

And the tests:

alert(window.location.querystring.toString());


for (var key in location.querystring) {
alert(key + "=" + location.querystring[key]);
}

Mind you thought, JavaScript isn't my native tongue.

Anyway, I'm looking for a JavaScript library (e.g. jQuery, Prototype) that already has one written. :)

function decode(s) {
try {
return decodeURIComponent(s).replace(/\r\n|\r|\n/g, "\r\n");
} catch (e) {
return "";
}
}
function getQueryString(win) {
var qs = win.location.search;
var multimap = {};
if (qs.length > 1) {
qs = qs.substr(1);
qs.replace(/([^=&]+)=([^&]*)/g, function(match, hfname, hfvalue) {
var name = decode(hfname);
var value = decode(hfvalue);
if (name.length > 0) {
if (!multimap.hasOwnProperty(name)) {
multimap[name] = [];
}
multimap[name].push(value);
}
});
}
return multimap;
}
var keys = getQueryString(window);
for (var i in keys) {
if (keys.hasOwnProperty(i)) {
for (var z = 0; z < keys[i].length; ++z) {
alert(i + ":" + keys[i][z]);
}
}
}

Maybe http://plugins.jquery.com/query-object/?

This is the fork of it https://github.com/sousk/jquery.parsequery#readme.

After finding this post, when looking myself I thought I should add that I don't think the most up-voted solution is the best. It doesn't handle array values (such as ?a=foo&a=bar - in this case I would expect getting a to return ['foo', 'bar']). It also as far as I can tell doesn't take into account encoded values - such as hex character encoding where %20 represents a space (example: ?a=Hello%20World) or the plus symbol being used to represent a space (example: ?a=Hello+World).

Node.js offers what looks like a very complete solutions to querystring parsing. It would be easy to take out and use in your own project as its fairly well isolated and under a permissive licence.

The code for it can be viewed here: https://github.com/joyent/node/blob/master/lib/querystring.js

The tests that Node has can be seen here: https://github.com/joyent/node/blob/master/test/simple/test-querystring.js I would suggest trying some of these with the popular answer to see how it handles them.

There is also a project that I was involved in to specifically add this functionality. It is a port of the Python standard lib query string parsing module. My fork can be found here: https://github.com/d0ugal/jquery.qeeree

If you have the querystring on hand, use this:

 /**
* @param qry the querystring
* @param name name of parameter
* @returns the parameter specified by name
* @author eduardo.medeirospereira@gmail.com
*/


function getQueryStringParameter(qry,name){
if(typeof qry !== undefined && qry !== ""){
var keyValueArray = qry.split("&");
for ( var i = 0; i < keyValueArray.length; i++) {
if(keyValueArray[i].indexOf(name)>-1){
return keyValueArray[i].split("=")[1];
}
}
}
return "";
}

Building on the answer by @CMS I have the following (in CoffeeScript which can easily be converted to JavaScript):

String::to_query = ->
[result, re, d] = [{}, /([^&=]+)=([^&]*)/g, decodeURIComponent]
while match = re.exec(if @.match /^\?/ then @.substring(1) else @)
result[d(match[1])] = d match[2]
result

You can easily grab what you need with:

location.search.to_query()['my_param']

The win here is an object-oriented interface (instead of functional) and it can be done on any string (not just location.search).

If you are already using a JavaScript library this function make already exist. For example here is Prototype's version

Or you could use the library sugar.js.

From sugarjs.com:

Object.fromQueryString ( str , deep = true )

Converts the query string of a URL into an object. If deep is false, conversion will only accept shallow params (ie. no object or arrays with [] syntax) as these are not universally supported.

Object.fromQueryString('foo=bar&broken=wear') >{"foo":"bar","broken":"wear"}
Object.fromQueryString('foo[]=1&foo[]=2') >{"foo":[1,2]}

Example:

var queryString = Object.fromQueryString(location.search);
var foo = queryString.foo;

tl;dr solution on a single(ish) line of code using vanilla javascript

var queryDict = {}
location.search.substr(1).split("&").forEach(function(item) {
queryDict[item.split("=")[0]] = item.split("=")[1]
})

For querystring ?a=1&b=2&c=3&d&eit returns:

> queryDict
a: "1"
b: "2"
c: "3"
d: undefined
e: undefined

multi-valued keys and encoded characters?

See the original answer at How can I get query string values in JavaScript?

"?a=1&b=2&c=3&d&e&a=5&a=t%20e%20x%20t&e=http%3A%2F%2Fw3schools.com%2Fmy%20test.asp%3Fname%3Dståle%26car%3Dsaab"
> queryDict
a: ["1", "5", "t e x t"]
b: ["2"]
c: ["3"]
d: [undefined]
e: [undefined, "http://w3schools.com/my test.asp?name=ståle&car=saab"]

// How about this
function queryString(qs) {
var queryStr = qs.substr(1).split("&"),obj={};
for(var i=0; i < queryStr.length;i++)
obj[queryStr[i].split("=")[0]] = queryStr[i].split("=")[1];
return obj;
}


// Usage:
var result = queryString(location.search);

I like to keep it simple, readable and small.

function searchToObject(search) {
var pairs = search.substring(1).split("&"),
obj = {}, pair;


for (var i in pairs) {
if (pairs[i] === "") continue;
pair = pairs[i].split("=");
obj[decodeURIComponent(pair[0])] = decodeURIComponent(pair[1]);
}
return obj;
}


searchToObject(location.search);

Example:

searchToObject('?query=myvalue')['query']; // spits out: 'myvalue'

Function I wrote for a requirement similar to this with pure javascript string manipulation

"http://www.google.lk/?Name=John&Age=20&Gender=Male"


function queryize(sampleurl){
var tokens = url.split('?')[1].split('&');
var result = {};


for(var i=0; i<tokens.length; i++){
result[tokens[i].split('=')[0]] = tokens[i].split('=')[1];
}


return result;
}

Usage:

queryize(window.location.href)['Name'] //returns John
queryize(window.location.href)['Age'] //returns 20
queryize(window.location.href)['Gender'] //returns Male

If you are using lodash + ES6, here is a one line solution: _.object(window.location.search.replace(/(^\?)/, '').split('&').map(keyVal => keyVal.split('=')));

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.

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. :/

Example:

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";
//var qs = "?=&=";
//var qs = ""


var results = querystring(qs);


(document.getElementById("results")).innerHTML =JSON.stringify(results, null, 2);

<script
src="https://rawgit.com/EldonMcGuinness/querystring.js/master/dist/querystring.min.js"></script>
<pre id="results">RESULTS: Waiting...</pre>