How to Parse a Url Query Parameters, in JavaScript

How can I get query string values in JavaScript?

Update: Jan-2022

Using Proxy() is faster than using Object.fromEntries() and better supported

const params = new Proxy(new URLSearchParams(window.location.search), {
  get: (searchParams, prop) => searchParams.get(prop),
});
// Get the value of "some_key" in eg "https://example.com/?some_key=some_value"
let value = params.some_key; // "some_value"

Update: June-2021

For a specific case when you need all query params:

const urlSearchParams = new URLSearchParams(window.location.search);
const params = Object.fromEntries(urlSearchParams.entries());

Update: Sep-2018

You can use URLSearchParams which is simple and has decent (but not complete) browser support.

const urlParams = new URLSearchParams(window.location.search);
const myParam = urlParams.get('myParam');

Original

You don't need jQuery for that purpose. You can use just some pure JavaScript:

function getParameterByName(name, url = window.location.href) {
    name = name.replace(/[\[\]]/g, '\\$&');
    var regex = new RegExp('[?&]' + name + '(=([^&#]*)|&|#|$)'),
        results = regex.exec(url);
    if (!results) return null;
    if (!results[2]) return '';
    return decodeURIComponent(results[2].replace(/\+/g, ' '));
}

Usage:

// query string: ?foo=lorem&bar=&baz
var foo = getParameterByName('foo'); // "lorem"
var bar = getParameterByName('bar'); // "" (present with empty value)
var baz = getParameterByName('baz'); // "" (present with no value)
var qux = getParameterByName('qux'); // null (absent)

NOTE: If a parameter is present several times (?foo=lorem&foo=ipsum), you will get the first value (lorem). There is no standard about this and usages vary, see for example this question: Authoritative position of duplicate HTTP GET query keys.

NOTE: The function is case-sensitive. If you prefer case-insensitive parameter name, add 'i' modifier to RegExp

NOTE: If you're getting a no-useless-escape eslint error, you can replace name = name.replace(/[\[\]]/g, '\\$&'); with name = name.replace(/[[\]]/g, '\\$&').

---

This is an update based on the new URLSearchParams specs to achieve the same result more succinctly. See answer titled "URLSearchParams" below.

How do I parse a URL query parameters, in Javascript?

Today (2.5 years after this answer) you can safely use Array.forEach. As @ricosrealm suggests, decodeURIComponent was used in this function.

function getJsonFromUrl(url) {
  if(!url) url = location.search;
  var query = url.substr(1);
  var result = {};
  query.split("&").forEach(function(part) {
    var item = part.split("=");
    result[item[0]] = decodeURIComponent(item[1]);
  });
  return result;
}

actually it's not that simple, see the peer-review in the comments, especially:

• hash based routing (@cmfolio)
• array parameters (@user2368055)
• proper use of decodeURIComponent and non-encoded = (@AndrewF)
• non-encoded + (added by me)

For further details, see MDN article and RFC 3986.

Maybe this should go to codereview SE, but here is safer and regexp-free code:

function getJsonFromUrl(url) {
  if(!url) url = location.href;
  var question = url.indexOf("?");
  var hash = url.indexOf("#");
  if(hash==-1 && question==-1) return {};
  if(hash==-1) hash = url.length;
  var query = question==-1 || hash==question+1 ? url.substring(hash) : 
  url.substring(question+1,hash);
  var result = {};
  query.split("&").forEach(function(part) {
    if(!part) return;
    part = part.split("+").join(" "); // replace every + with space, regexp-free version
    var eq = part.indexOf("=");
    var key = eq>-1 ? part.substr(0,eq) : part;
    var val = eq>-1 ? decodeURIComponent(part.substr(eq+1)) : "";
    var from = key.indexOf("[");
    if(from==-1) result[decodeURIComponent(key)] = val;
    else {
      var to = key.indexOf("]",from);
      var index = decodeURIComponent(key.substring(from+1,to));
      key = decodeURIComponent(key.substring(0,from));
      if(!result[key]) result[key] = [];
      if(!index) result[key].push(val);
      else result[key][index] = val;
    }
  });
  return result;
}

This function can parse even URLs like

var url = "?foo%20e[]=a%20a&foo+e[%5Bx%5D]=b&foo e[]=c";
// {"foo e": ["a a",  "c",  "[x]":"b"]}

var obj = getJsonFromUrl(url)["foo e"];
for(var key in obj) { // Array.forEach would skip string keys here
  console.log(key,":",obj[key]);
}
/*
  0 : a a
  1 : c
  [x] : b
*/

How to convert URL parameters to a JavaScript object?

In the year 2021... Please consider this obsolete.

Edit

This edit improves and explains the answer based on the comments.

var search = location.search.substring(1);
JSON.parse('{"' + decodeURI(search).replace(/"/g, '\\"').replace(/&/g, '","').replace(/=/g,'":"') + '"}')

Example

Parse abc=foo&def=%5Basf%5D&xyz=5 in five steps:

• decodeURI: abc=foo&def=[asf]&xyz=5
• Escape quotes: same, as there are no quotes
• Replace &: abc=foo","def=[asf]","xyz=5
• Replace =: abc":"foo","def":"[asf]","xyz":"5
• Suround with curlies and quotes: {"abc":"foo","def":"[asf]","xyz":"5"}

which is legal JSON.

An improved solution allows for more characters in the search string. It uses a reviver function for URI decoding:

var search = location.search.substring(1);
JSON.parse('{"' + search.replace(/&/g, '","').replace(/=/g,'":"') + '"}', function(key, value) { return key===""?value:decodeURIComponent(value) })

Example

search = "abc=foo&def=%5Basf%5D&xyz=5&foo=b%3Dar";

gives

Object {abc: "foo", def: "[asf]", xyz: "5", foo: "b=ar"}

Original answer

A one-liner:

JSON.parse('{"' + decodeURI("abc=foo&def=%5Basf%5D&xyz=5".replace(/&/g, "\",\"").replace(/=/g,"\":\"")) + '"}')

How do I parse a URL for a specific Query Paramter in javascript?

David here, from the Zapier Platform team.

While the comments above point you towards regex, I recommend a more native approach: actually parsing the url. Node.js has a great standard library for doing that:

// the following line is set up in the zapier UI; uncomment if you want to test locally
// const inputData = {url: 'https://www.example.com/landing-page/?aid=1234'}

const url = require('url')
const querystring = require('querystring')

const urlObj = url.parse(inputData.url) /*
Url {
  protocol: 'https:',
  slashes: true,
  auth: null,
  host: 'www.example.com',
  port: null,
  hostname: 'www.example.com',
  hash: null,
  search: '?aid=1234',
  query: 'aid=1234',
  pathname: '/landing-page/',
  path: '/landing-page/?aid=1234',
  href: 'https://www.example.com/landing-page/?aid=1234' }
*/
const qsObj = querystring.parse(urlObj.query) // { aid: '1234' }

return { aid: qsObj.aid }

Depending on how confident you are that the data you're looking for will always be there, you may have to do some fallbacks here, but this will very reliably find the param(s) you're looking for. You could also follow this code step with a Filter to ensure latter steps that depend on the aid don't run if it's missing.

​Let me know if you've got any other questions!

How can I get query string values in JavaScript?

Update: Jan-2022

Using Proxy() is faster than using Object.fromEntries() and better supported

const params = new Proxy(new URLSearchParams(window.location.search), {
  get: (searchParams, prop) => searchParams.get(prop),
});
// Get the value of "some_key" in eg "https://example.com/?some_key=some_value"
let value = params.some_key; // "some_value"

Update: June-2021

For a specific case when you need all query params:

const urlSearchParams = new URLSearchParams(window.location.search);
const params = Object.fromEntries(urlSearchParams.entries());

Update: Sep-2018

You can use URLSearchParams which is simple and has decent (but not complete) browser support.

const urlParams = new URLSearchParams(window.location.search);
const myParam = urlParams.get('myParam');

Original

You don't need jQuery for that purpose. You can use just some pure JavaScript:

function getParameterByName(name, url = window.location.href) {
    name = name.replace(/[\[\]]/g, '\\$&');
    var regex = new RegExp('[?&]' + name + '(=([^&#]*)|&|#|$)'),
        results = regex.exec(url);
    if (!results) return null;
    if (!results[2]) return '';
    return decodeURIComponent(results[2].replace(/\+/g, ' '));
}

Usage:

// query string: ?foo=lorem&bar=&baz
var foo = getParameterByName('foo'); // "lorem"
var bar = getParameterByName('bar'); // "" (present with empty value)
var baz = getParameterByName('baz'); // "" (present with no value)
var qux = getParameterByName('qux'); // null (absent)

NOTE: If a parameter is present several times (?foo=lorem&foo=ipsum), you will get the first value (lorem). There is no standard about this and usages vary, see for example this question: Authoritative position of duplicate HTTP GET query keys.

NOTE: The function is case-sensitive. If you prefer case-insensitive parameter name, add 'i' modifier to RegExp

NOTE: If you're getting a no-useless-escape eslint error, you can replace name = name.replace(/[\[\]]/g, '\\$&'); with name = name.replace(/[[\]]/g, '\\$&').

---

This is an update based on the new URLSearchParams specs to achieve the same result more succinctly. See answer titled "URLSearchParams" below.

Parse search params in relative URL in Javascript

You could take everything after the ? and pass it directly to URLSearchParams.

const getParamsFromURI = ( uri ) => {
  // Get everything after the `?`
  const [ , paramString ] = uri.split( '?' );

  // Return parameters
  return new URLSearchParams( paramString );
};

const params = getParamsFromURI( '/a/b?someParam=cccc' );
console.log( params.get( 'someParam' ) );

---

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