Adding a parameter to the URL with JavaScript

Javascript Url Parsing Parameters Query String

Javascript Problem Overview

In a web application that makes use of AJAX calls, I need to submit a request but add a parameter to the end of the URL, for example:

Original URL: > http://server/myapp.php?id=10

Resulting URL: > http://server/myapp.php?id=10**&enabled=true**

Looking for a JavaScript function which parses the URL looking at each parameter, then adds the new parameter or updates the value if one already exists.

Javascript Solutions

Solution 1 - Javascript

You can use one of these:

Example:

var url = new URL("http://foo.bar/?x=1&y=2");

// If your expected result is "http://foo.bar/?x=1&y=2&x=42"
url.searchParams.append('x', 42);

// If your expected result is "http://foo.bar/?x=42&y=2"
url.searchParams.set('x', 42);

You can use url.href or url.toString() to get the full URL

Solution 2 - Javascript

A basic implementation which you'll need to adapt would look something like this:

function insertParam(key, value) {
    key = encodeURIComponent(key);
    value = encodeURIComponent(value);

    // kvp looks like ['key1=value1', 'key2=value2', ...]
    var kvp = document.location.search.substr(1).split('&');
    let i=0;
        
    for(; i<kvp.length; i++){
        if (kvp[i].startsWith(key + '=')) {
            let pair = kvp[i].split('=');
            pair[1] = value;
            kvp[i] = pair.join('=');
            break;
        }
    }
    
    if(i >= kvp.length){
        kvp[kvp.length] = [key,value].join('=');
    }

    // can return this or...
    let params = kvp.join('&');

    // reload page with new params
    document.location.search = params;
}

This is approximately twice as fast as a regex or search based solution, but that depends completely on the length of the querystring and the index of any match

the slow regex method I benchmarked against for completions sake (approx +150% slower)

function insertParam2(key,value)
{
	key = encodeURIComponent(key); value = encodeURIComponent(value);

	var s = document.location.search;
	var kvp = key+"="+value;
	
	var r = new RegExp("(&|\\?)"+key+"=[^\&]*");
	
	s = s.replace(r,"$1"+kvp);

	if(!RegExp.$1) {s += (s.length>0 ? '&' : '?') + kvp;};

	//again, do what you will here
	document.location.search = s;
}

Solution 3 - Javascript

You can use URLSearchParams

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

urlParams.set('order', 'date');

window.location.search = urlParams;

.set first agrument is the key, the second one is the value.

Note: this is not supported in any version of Internet Explorer (but is supported in Edge)

Solution 4 - Javascript

Thank you all for your contribution. I used annakata code and modified to also include the case where there is no query string in the url at all. Hope this would help.

function insertParam(key, value) {
        key = escape(key); value = escape(value);

        var kvp = document.location.search.substr(1).split('&');
        if (kvp == '') {
            document.location.search = '?' + key + '=' + value;
        }
        else {

            var i = kvp.length; var x; while (i--) {
                x = kvp[i].split('=');

                if (x[0] == key) {
                    x[1] = value;
                    kvp[i] = x.join('=');
                    break;
                }
            }

            if (i < 0) { kvp[kvp.length] = [key, value].join('='); }

            //this will reload the page, it's likely better to store this until finished
            document.location.search = kvp.join('&');
        }
    }

Solution 5 - Javascript

This is very simple solution. Its doesn't control parameter existence, and it doesn't change existing value. It adds your parameter to end, so you can get latest value in your back-end code.

function addParameterToURL(param){
	_url = location.href;
	_url += (_url.split('?')[1] ? '&':'?') + param;
	return _url;
}

Solution 6 - Javascript

Here's a vastly simplified version, making tradeoffs for legibility and fewer lines of code instead of micro-optimized performance (and we're talking about a few miliseconds difference, realistically... due to the nature of this (operating on the current document's location), this will most likely be ran once on a page).

/**
* Add a URL parameter (or changing it if it already exists)
* @param {search} string  this is typically document.location.search
* @param {key}    string  the key to set
* @param {val}    string  value 
*/
var addUrlParam = function(search, key, val){
  var newParam = key + '=' + val,
      params = '?' + newParam;

  // If the "search" string exists, then build params from it
  if (search) {
    // Try to replace an existance instance
    params = search.replace(new RegExp('([?&])' + key + '[^&]*'), '$1' + newParam);

    // If nothing was replaced, then add the new param to the end
    if (params === search) {
      params += '&' + newParam;
    }
  }

  return params;
};

You would then use this like so:

document.location.pathname + addUrlParam(document.location.search, 'foo', 'bar');

Solution 7 - Javascript

There is a built-in function inside URL class that you can use it for easy dealing with query string key/value params:

const url = new URL(window.location.href);
// url.searchParams has several function, we just use `set` function
// to set a value, if you just want to append without replacing value
// let use `append` function

url.searchParams.set('key', 'value');

console.log(url.search) // <== '?key=value'

// if window.location.href has already some qs params this `set` function
// modify or append key/value in it

For more information about searchParams functions.

URL is not supported in IE, check compatibility

Solution 8 - Javascript

/** * Add a URL parameter * @param {string} url * @param {string} param the key to set * @param {string} value */ var addParam = function(url, param, value) { param = encodeURIComponent(param); var a = document.createElement('a'); param += (value ? "=" + encodeURIComponent(value) : ""); a.href = url; a.search += (a.search ? "&" : "") + param; return a.href; }

/**
* Add a URL parameter (or modify if already exists)
* @param {string} url 
* @param {string} param the key to set
* @param {string} value 
*/

url = "http://www.example.com#hashme";; newurl = addParam(url, "ciao", "1"); alert(newurl);

And please note that parameters should be encoded before being appended in query string.

http://jsfiddle.net/48z7z4kx/

Solution 9 - Javascript

I have a 'class' that does this and here it is:

function QS(){
    this.qs = {};
    var s = location.search.replace( /^\?|#.*$/g, '' );
    if( s ) {
        var qsParts = s.split('&');
        var i, nv;
        for (i = 0; i < qsParts.length; i++) {
            nv = qsParts[i].split('=');
            this.qs[nv[0]] = nv[1];
        }
    }
}
  
QS.prototype.add = function( name, value ) {
    if( arguments.length == 1 && arguments[0].constructor == Object ) {
        this.addMany( arguments[0] );
        return;
    }
    this.qs[name] = value;
}

QS.prototype.addMany = function( newValues ) {
    for( nv in newValues ) {
        this.qs[nv] = newValues[nv];
    }
}

QS.prototype.remove = function( name ) {
    if( arguments.length == 1 && arguments[0].constructor == Array ) {
        this.removeMany( arguments[0] );
        return;
    }
    delete this.qs[name];
}

QS.prototype.removeMany = function( deleteNames ) {
    var i;
    for( i = 0; i < deleteNames.length; i++ ) {
        delete this.qs[deleteNames[i]];
    }
}

QS.prototype.getQueryString = function() {
    var nv, q = [];
    for( nv in this.qs ) {
        q[q.length] = nv+'='+this.qs[nv];
    }
    return q.join( '&' );
}

QS.prototype.toString = QS.prototype.getQueryString;

//examples
//instantiation
var qs = new QS;
alert( qs );

//add a sinle name/value
qs.add( 'new', 'true' );
alert( qs );

//add multiple key/values
qs.add( { x: 'X', y: 'Y' } );
alert( qs );

//remove single key
qs.remove( 'new' )
alert( qs );

//remove multiple keys
qs.remove( ['x', 'bogus'] )
alert( qs );

I have overridden the toString method so there is no need to call QS::getQueryString, you can use QS::toString or, as I have done in the examples just rely on the object being coerced into a string.

Solution 10 - Javascript

If you have a string with url that you want to decorate with a param, you could try this oneliner:

urlstring += ( urlstring.match( /[\?]/g ) ? '&' : '?' ) + 'param=value';

This means that ? will be the prefix of the parameter, but if you already have ? in urlstring, than & will be the prefix.

I would also recommend to do encodeURI( paramvariable ) if you didn't hardcoded parameter, but it is inside a paramvariable; or if you have funny characters in it.

See javascript URL Encoding for usage of the encodeURI function.

Solution 11 - Javascript

This is a simple way to add a query parameter:

const query = new URLSearchParams(window.location.search);
query.append("enabled", "true");

And that is it more here.

Please note the support specs.

Solution 12 - Javascript

Sometime we see ? at the end URL, i found some solutions which generate results as file.php?&foo=bar. i came up with my own solution work perfectly as i want!

location.origin + location.pathname + location.search + (location.search=='' ? '?' : '&') + 'lang=ar'

Note: location.origin doesn't work in IE, here is its fix.

Solution 13 - Javascript

Following function will help you to add,update and delete parameters to or from URL.

//example1and

var myURL = '/search';

myURL = updateUrl(myURL,'location','california');
console.log('added location...' + myURL);
//added location.../search?location=california

myURL = updateUrl(myURL,'location','new york');
console.log('updated location...' + myURL);
//updated location.../search?location=new%20york

myURL = updateUrl(myURL,'location');
console.log('removed location...' + myURL);
//removed location.../search

//example2

var myURL = '/search?category=mobile';

myURL = updateUrl(myURL,'location','california');
console.log('added location...' + myURL);
//added location.../search?category=mobile&location=california

myURL = updateUrl(myURL,'location','new york');
console.log('updated location...' + myURL);
//updated location.../search?category=mobile&location=new%20york

myURL = updateUrl(myURL,'location');
console.log('removed location...' + myURL);
//removed location.../search?category=mobile

//example3

var myURL = '/search?location=texas';

myURL = updateUrl(myURL,'location','california');
console.log('added location...' + myURL);
//added location.../search?location=california

myURL = updateUrl(myURL,'location','new york');
console.log('updated location...' + myURL);
//updated location.../search?location=new%20york

myURL = updateUrl(myURL,'location');
console.log('removed location...' + myURL);
//removed location.../search

//example4

var myURL = '/search?category=mobile&location=texas';

myURL = updateUrl(myURL,'location','california');
console.log('added location...' + myURL);
//added location.../search?category=mobile&location=california

myURL = updateUrl(myURL,'location','new york');
console.log('updated location...' + myURL);
//updated location.../search?category=mobile&location=new%20york

myURL = updateUrl(myURL,'location');
console.log('removed location...' + myURL);
//removed location.../search?category=mobile

//example5

var myURL = 'https://example.com/search?location=texas#fragment';

myURL = updateUrl(myURL,'location','california');
console.log('added location...' + myURL);
//added location.../search?location=california#fragment

myURL = updateUrl(myURL,'location','new york');
console.log('updated location...' + myURL);
//updated location.../search?location=new%20york#fragment

myURL = updateUrl(myURL,'location');
console.log('removed location...' + myURL);
//removed location.../search#fragment

Here is the function.

function updateUrl(url,key,value){
      if(value!==undefined){
        value = encodeURI(value);
      }
      var hashIndex = url.indexOf("#")|0;
      if (hashIndex === -1) hashIndex = url.length|0;
      var urls = url.substring(0, hashIndex).split('?');
      var baseUrl = urls[0];
      var parameters = '';
      var outPara = {};
      if(urls.length>1){
          parameters = urls[1];
      }
      if(parameters!==''){
        parameters = parameters.split('&');
        for(k in parameters){
          var keyVal = parameters[k];
          keyVal = keyVal.split('=');
          var ekey = keyVal[0];
          var evalue = '';
          if(keyVal.length>1){
              evalue = keyVal[1];
          }
          outPara[ekey] = evalue;
        }
      }

      if(value!==undefined){
        outPara[key] = value;
      }else{
        delete outPara[key];
      }
      parameters = [];
      for(var k in outPara){
        parameters.push(k + '=' + outPara[k]);
      }
      
      var finalUrl = baseUrl;

      if(parameters.length>0){
        finalUrl += '?' + parameters.join('&'); 
      }

      return finalUrl + url.substring(hashIndex); 
  }

Solution 14 - Javascript

This solution updates the window's current URL with updated search parameters without actually reloading the page. This approach is useful in a PWA/SPA context.

function setURLSearchParam(key, value) {
  const url = new URL(window.location.href);
  url.searchParams.set(key, value);
  window.history.pushState({ path: url.href }, '', url.href);
}

Solution 15 - Javascript

This was my own attempt, but I'll use the answer by annakata as it seems much cleaner:

function AddUrlParameter(sourceUrl, parameterName, parameterValue, replaceDuplicates)
{
	if ((sourceUrl == null) || (sourceUrl.length == 0)) sourceUrl = document.location.href;
	var urlParts = sourceUrl.split("?");
	var newQueryString = "";
	if (urlParts.length > 1)
	{
		var parameters = urlParts[1].split("&");
		for (var i=0; (i < parameters.length); i++)
		{
			var parameterParts = parameters[i].split("=");
			if (!(replaceDuplicates && parameterParts[0] == parameterName))
			{
				if (newQueryString == "")
					newQueryString = "?";
				else
					newQueryString += "&";
				newQueryString += parameterParts[0] + "=" + parameterParts[1];
			}
		}
	}
	if (newQueryString == "")
		newQueryString = "?";
	else
		newQueryString += "&";
	newQueryString += parameterName + "=" + parameterValue;

	return urlParts[0] + newQueryString;
}

Also, I found this jQuery plugin from another post on stackoverflow, and if you need more flexibility you could use that: http://plugins.jquery.com/project/query-object

I would think the code would be (haven't tested):

return $.query.parse(sourceUrl).set(parameterName, parameterValue).toString();

Solution 16 - Javascript

Check out <https://github.com/derek-watson/jsUri>

Uri and query string manipulation in javascript.

This project incorporates the excellent parseUri regular expression library by Steven Levithan. You can safely parse URLs of all shapes and sizes, however invalid or hideous.

Solution 17 - Javascript

Try this.

// uses the URL class
function setParam(key, value) {
            let url = new URL(window.document.location);
            let params = new URLSearchParams(url.search.slice(1));

            if (params.has(key)) {
                params.set(key, value);
            }else {
                params.append(key, value);
            }
        }

Solution 18 - Javascript

Adding to @Vianney's Answer https://stackoverflow.com/a/44160941/6609678

We can import the Built-in URL module in node as follows

const { URL } = require('url');

Example:

Terminal $ node
> const { URL } = require('url');
undefined
> let url = new URL('', 'http://localhost:1989/v3/orders');
undefined
> url.href
'http://localhost:1989/v3/orders'
> let fetchAll=true, timePeriod = 30, b2b=false;
undefined
> url.href
'http://localhost:1989/v3/orders'
>  url.searchParams.append('fetchAll', fetchAll);
undefined
>  url.searchParams.append('timePeriod', timePeriod);
undefined
>  url.searchParams.append('b2b', b2b);
undefined
> url.href
'http://localhost:1989/v3/orders?fetchAll=true&timePeriod=30&b2b=false'
> url.toString()
'http://localhost:1989/v3/orders?fetchAll=true&timePeriod=30&b2b=false'

Useful Links:

https://developer.mozilla.org/en-US/docs/Web/API/URL https://developer.mozilla.org/en/docs/Web/API/URLSearchParams

Solution 19 - Javascript

It handles such URL's:

empty
doesn't have any parameters
already have some parameters
have ? at the end, but at the same time doesn't have any parameters

It doesn't handles such URL's:

with fragment identifier (i.e. hash, #)
if URL already have required query parameter (then there will be duplicate)

Works in:

Chrome 32+
Firefox 26+
Safari 7.1+

function appendQueryParameter(url, name, value) {
    if (url.length === 0) {
        return;
    }

    let rawURL = url;

    // URL with `?` at the end and without query parameters
    // leads to incorrect result.
    if (rawURL.charAt(rawURL.length - 1) === "?") {
        rawURL = rawURL.slice(0, rawURL.length - 1);
    }

    const parsedURL = new URL(rawURL);
    let parameters = parsedURL.search;

    parameters += (parameters.length === 0) ? "?" : "&";
    parameters = (parameters + name + "=" + value);

    return (parsedURL.origin + parsedURL.pathname + parameters);
}

Version with ES6 template strings.

Works in:

Chrome 41+
Firefox 32+
Safari 9.1+

function appendQueryParameter(url, name, value) {
    if (url.length === 0) {
        return;
    }

    let rawURL = url;

    // URL with `?` at the end and without query parameters
    // leads to incorrect result.
    if (rawURL.charAt(rawURL.length - 1) === "?") {
        rawURL = rawURL.slice(0, rawURL.length - 1);
    }

    const parsedURL = new URL(rawURL);
    let parameters = parsedURL.search;

    parameters += (parameters.length === 0) ? "?" : "&";
    parameters = `${parameters}${name}=${value}`;

    return `${parsedURL.origin}${parsedURL.pathname}${parameters}`;
}

Solution 20 - Javascript

Vianney Bajart's answer is correct; however, URL will only work if you have the complete URL with port, host, path and query:

new URL('http://server/myapp.php?id=10&enabled=true')

And URLSearchParams will only work if you pass only the query string:

new URLSearchParams('?id=10&enabled=true')

If you have an incomplete or relative URL and don't care for the base URL, you can just split by ? to get the query string and join later like this:

function setUrlParams(url, key, value) {
  url = url.split('?');
  usp = new URLSearchParams(url[1]);
  usp.set(key, value);
  url[1] = usp.toString();
  return url.join('?');
}

let url = 'myapp.php?id=10';
url = setUrlParams(url, 'enabled', true);  // url = 'myapp.php?id=10&enabled=true'
url = setUrlParams(url, 'id', 11);         // url = 'myapp.php?id=11&enabled=true'

Not compatible with Internet Explorer.

Solution 21 - Javascript

I like the answer of Mehmet Fatih Yıldız even he did not answer the whole question.

In the same line as his answer, I use this code:

"Its doesn't control parameter existence, and it doesn't change existing value. It adds your parameter to the end"

  /** add a parameter at the end of the URL. Manage '?'/'&', but not the existing parameters.
   *  does escape the value (but not the key)
   */
  function addParameterToURL(_url,_key,_value){
  	  var param = _key+'='+escape(_value);
  	  
  	  var sep = '&';
  	  if (_url.indexOf('?') < 0) {
  	    sep = '?';
  	  } else {
  	    var lastChar=_url.slice(-1);
  	    if (lastChar == '&') sep='';
  	    if (lastChar == '?') sep='';
  	  }
      _url += sep + param;
      
      return _url;
  }

and the tester:

  /*
  function addParameterToURL_TESTER_sub(_url,key,value){
    //log(_url);
    log(addParameterToURL(_url,key,value));
  }
  
  function addParameterToURL_TESTER(){
  	log('-------------------');
  	var _url ='www.google.com';
  	addParameterToURL_TESTER_sub(_url,'key','value');
  	addParameterToURL_TESTER_sub(_url,'key','Text Value');
  	_url ='www.google.com?';
  	addParameterToURL_TESTER_sub(_url,'key','value');
  	_url ='www.google.com?A=B';
  	addParameterToURL_TESTER_sub(_url,'key','value');
  	_url ='www.google.com?A=B&';
  	addParameterToURL_TESTER_sub(_url,'key','value');
  	_url ='www.google.com?A=1&B=2';
  	addParameterToURL_TESTER_sub(_url,'key','value');
  	
  }//*/

Solution 22 - Javascript

I would go with this small but complete library to handle urls in js:

https://github.com/Mikhus/jsurl

Solution 23 - Javascript

This is what I use when it comes to some basic url param additions or updates on the server-side like Node.js.

CoffeScript:

###
    @method addUrlParam Adds parameter to a given url. If the parameter already exists in the url is being replaced.
    @param {string} url
    @param {string} key Parameter's key
    @param {string} value Parameter's value
    @returns {string} new url containing the parameter
###
addUrlParam = (url, key, value) ->
    newParam = key+"="+value
    result = url.replace(new RegExp('(&|\\?)' + key + '=[^\&|#]*'), '$1' + newParam)
    if result is url
        result = if url.indexOf('?') != -1 then url.split('?')[0] + '?' + newParam + '&' + url.split('?')[1]
    else if url.indexOf('#') != -1 then url.split('#')[0] + '?' + newParam + '#' + url.split('#')[1]
    else url + '?' + newParam
    return result

JavaScript:

function addUrlParam(url, key, value) {
    var newParam = key+"="+value;
    var result = url.replace(new RegExp("(&|\\?)"+key+"=[^\&|#]*"), '$1' + newParam);
    if (result === url) { 
        result = (url.indexOf("?") != -1 ? url.split("?")[0]+"?"+newParam+"&"+url.split("?")[1] 
           : (url.indexOf("#") != -1 ? url.split("#")[0]+"?"+newParam+"#"+ url.split("#")[1] 
              : url+'?'+newParam));
    }
    return result;
}

var url = "http://www.example.com?foo=bar&ciao=3&doom=5#hashme";
result1.innerHTML = addUrlParam(url, "ciao", "1");

<p id="result1"></p>

Solution 24 - Javascript

Easiest solution, works if you have already a tag or not, and removes it automatically so it wont keep adding equal tags, have fun

function changeURL(tag)
{
if(window.location.href.indexOf("?") > -1) {
	if(window.location.href.indexOf("&"+tag) > -1){
		
		var url = window.location.href.replace("&"+tag,"")+"&"+tag;
	}
	else
	{
		var url = window.location.href+"&"+tag;
	}
}else{
	if(window.location.href.indexOf("?"+tag) > -1){
		
		var url = window.location.href.replace("?"+tag,"")+"?"+tag;
	}
	else
	{
		var url = window.location.href+"?"+tag;
	}
}
  window.location = url;
}

THEN

changeURL("i=updated");

Solution 25 - Javascript

I am adding my solution because it supports relative urls in addition to absolute urls. It is otherwise the same as the top answer which also uses Web API.

/**
 * updates a relative or absolute
 * by setting the search query with
 * the passed key and value.
 */
export const setQueryParam = (url, key, value) => {
  const dummyBaseUrl = 'https://dummy-base-url.com';
  const result = new URL(url, dummyBaseUrl);
  result.searchParams.set(key, value);
  return result.toString().replace(dummyBaseUrl, '');
};

And some jest tests:

// some jest tests
describe('setQueryParams', () => {
  it('sets param on relative url with base path', () => {
    // act
    const actual = setQueryParam(
      '/', 'ref', 'some-value',
    );
    // assert
    expect(actual).toEqual('/?ref=some-value');
  });
  it('sets param on relative url with no path', () => {
    // act
    const actual = setQueryParam(
      '', 'ref', 'some-value',
    );
    // assert
    expect(actual).toEqual('/?ref=some-value');
  });
  it('sets param on relative url with some path', () => {
    // act
    const actual = setQueryParam(
      '/some-path', 'ref', 'some-value',
    );
    // assert
    expect(actual).toEqual('/some-path?ref=some-value');
  });
  it('overwrites existing param', () => {
    // act
    const actual = setQueryParam(
      '/?ref=prev-value', 'ref', 'some-value',
    );
    // assert
    expect(actual).toEqual('/?ref=some-value');
  });
  it('sets param while another param exists', () => {
    // act
    const actual = setQueryParam(
      '/?other-param=other-value', 'ref', 'some-value',
    );
    // assert
    expect(actual).toEqual('/?other-param=other-value&ref=some-value');
  });
  it('honors existing base url', () => {
    // act
    const actual = setQueryParam(
      'https://base.com', 'ref', 'some-value',
    );
    // assert
    expect(actual).toEqual('https://base.com/?ref=some-value');
  });
  it('honors existing base url with some path', () => {
    // act
    const actual = setQueryParam(
      'https://base.com/some-path', 'ref', 'some-value',
    );
    // assert
    expect(actual).toEqual('https://base.com/some-path?ref=some-value');
  });
});

Solution 26 - Javascript

If you're messing around with urls in links or somewhere else, you may have to take the hash into account as well. Here's a fairly simple to understand solution. Probably not the FASTEST since it uses a regex... but in 99.999% of cases, the difference really doesn't matter!

function addQueryParam( url, key, val ){
    var parts = url.match(/([^?#]+)(\?[^#]*)?(\#.*)?/);
    var url = parts[1];
    var qs = parts[2] || '';
    var hash = parts[3] || '';

    if ( !qs ) {
        return url + '?' + key + '=' + encodeURIComponent( val ) + hash;
    } else {
        var qs_parts = qs.substr(1).split("&");
        var i;
        for (i=0;i<qs_parts.length;i++) {
            var qs_pair = qs_parts[i].split("=");
            if ( qs_pair[0] == key ){
                qs_parts[ i ] = key + '=' + encodeURIComponent( val );
                break;
            }
        }
        if ( i == qs_parts.length ){
            qs_parts.push( key + '=' + encodeURIComponent( val ) );
        }
        return url + '?' + qs_parts.join('&') + hash;
    }
}

Solution 27 - Javascript

The following:

Merges duplicate query string params
Works with absolute and relative URLs
Works in the browser and node

/**
 * Adds query params to existing URLs (inc merging duplicates)
 * @param {string} url - src URL to modify
 * @param {object} params - key/value object of params to add
 * @returns {string} modified URL
 */
function addQueryParamsToUrl(url, params) {

    // if URL is relative, we'll need to add a fake base
    var fakeBase = !url.startsWith('http') ? 'http://fake-base.com' : undefined;
    var modifiedUrl = new URL(url || '', fakeBase);

    // add/update params
    Object.keys(params).forEach(function(key) {
        if (modifiedUrl.searchParams.has(key)) {
            modifiedUrl.searchParams.set(key, params[key]);
        }
        else {
            modifiedUrl.searchParams.append(key, params[key]);
        }
    });

    // return as string (remove fake base if present)
    return modifiedUrl.toString().replace(fakeBase, '');
}

Examples:

// returns /guides?tag=api
addQueryParamsToUrl('/guides?tag=hardware', { tag:'api' })

// returns https://orcascan.com/guides?tag=api
addQueryParamsToUrl('https://orcascan.com/guides?tag=hardware', { tag: 'api' })

Solution 28 - Javascript

const params = new URLSearchParams(window.location.search);

params.delete(key)
window.history.replaceState({}, "", decodeURIComponent(`${window.location.pathname}?${params}`));

Solution 29 - Javascript

Ok here I compare Two functions, one made by myself (regExp) and another one made by (annakata).

Split array:

function insertParam(key, value)
{
    key = escape(key); value = escape(value);

    var kvp = document.location.search.substr(1).split('&');

    var i=kvp.length; var x; while(i--) 
    {
        x = kvp[i].split('=');

        if (x[0]==key)
        {
                x[1] = value;
                kvp[i] = x.join('=');
                break;
        }
    }

    if(i<0) {kvp[kvp.length] = [key,value].join('=');}

    //this will reload the page, it's likely better to store this until finished
    return "&"+kvp.join('&'); 
}

Regexp method:

function addParameter(param, value)
{
    var regexp = new RegExp("(\\?|\\&)" + param + "\\=([^\\&]*)(\\&|$)");
    if (regexp.test(document.location.search)) 
        return (document.location.search.toString().replace(regexp, function(a, b, c, d)
        {
                return (b + param + "=" + value + d);
        }));
    else 
        return document.location.search+ param + "=" + value;
}

Testing case:

time1=(new Date).getTime();
for (var i=0;i<10000;i++)
{
addParameter("test","test");
}
time2=(new Date).getTime();
for (var i=0;i<10000;i++)
{
insertParam("test","test");
}

time3=(new Date).getTime();

console.log((time2-time1)+" "+(time3-time2));

It seems that even with simplest solution (when regexp use only test and do not enter .replace function) it is still slower than spliting... Well. Regexp is kinda slow but... uhh...

Solution 30 - Javascript

Here is what I do. Using my editParams() function, you can add, remove, or change any parameter, then use the built in replaceState() function to update the URL:

window.history.replaceState('object or string', 'Title', 'page.html' + editParams('enable', 'true'));


// background functions below:

// add/change/remove URL parameter
// use a value of false to remove parameter
// returns a url-style string
function editParams (key, value) {
  key = encodeURI(key);

  var params = getSearchParameters();

  if (Object.keys(params).length === 0) {
    if (value !== false)
      return '?' + key + '=' + encodeURI(value);
    else
      return '';
  }
  
  if (value !== false)
    params[key] = encodeURI(value);
  else
    delete params[key];

  if (Object.keys(params).length === 0)
    return '';

  return '?' + $.map(params, function (value, key) {
    return key + '=' + value;
  }).join('&');
}

// Get object/associative array of URL parameters
function getSearchParameters () {
  var prmstr = window.location.search.substr(1);
  return prmstr !== null && prmstr !== "" ? transformToAssocArray(prmstr) : {};
}

// convert parameters from url-style string to associative array
function transformToAssocArray (prmstr) {
  var params = {},
      prmarr = prmstr.split("&");

  for (var i = 0; i < prmarr.length; i++) {
    var tmparr = prmarr[i].split("=");
    params[tmparr[0]] = tmparr[1];
  }
  return params;
}

Solution 31 - Javascript

As best I can tell none of the above answers address the case where the query string contains parameters which are themselves an array and hence will appear more than once, e.g:

http://example.com?sizes[]=a&sizes[]=b

The following function is what I wrote to update document.location.search. It takes an array of key/value pair arrays as an argument and it will return a revised version of the latter which you can do whatever you'd like with. I'm using it like this:

var newParams = [
    ['test','123'],
    ['best','456'],
    ['sizes[]','XXL']
];
var newUrl = document.location.pathname + insertParams(newParams);
history.replaceState('', '', newUrl);

If the current url was:

http://example.com/index.php?test=replaceme&sizes[]=XL

This would get you

http://example.com/index.php?test=123&sizes[]=XL&sizes[]=XXL&best=456

Function

function insertParams(params) {
	var result;
	var ii = params.length;
	var queryString = document.location.search.substr(1);
	var kvps = queryString ? queryString.split('&') : [];
	var kvp;
	var skipParams = [];
	var i = kvps.length;
	while (i--) {
		kvp = kvps[i].split('=');
		if (kvp[0].slice(-2) != '[]') {
			var ii = params.length;
			while (ii--) {
				if (params[ii][0] == kvp[0]) {
					kvp[1] = params[ii][1];
					kvps[i] = kvp.join('=');
					skipParams.push(ii);
				}
			}
		}
	}
	var ii = params.length;
	while (ii--) {
		if (skipParams.indexOf(ii) === -1) {
			kvps.push(params[ii].join('='));
		}
	}
	result = kvps.length ? '?' + kvps.join('&') : '';
	return result;
}

Solution 32 - Javascript

Try
The regular expressions, so slow, thus:

var SetParamUrl = function(_k, _v) {// replace and add new parameters

	let arrParams = window.location.search !== '' ? decodeURIComponent(window.location.search.substr(1)).split('&').map(_v => _v.split('=')) : Array();
	let index = arrParams.findIndex((_v) => _v[0] === _k); 
	index = index !== -1 ? index : arrParams.length;
	_v === null ? arrParams = arrParams.filter((_v, _i) => _i != index) : arrParams[index] = [_k, _v];
	let _search = encodeURIComponent(arrParams.map(_v => _v.join('=')).join('&'));

	let newurl = window.location.protocol + "//" + window.location.host + window.location.pathname + (arrParams.length > 0 ? '?' +  _search : ''); 
	
	// window.location = newurl; //reload 
	
	if (history.pushState) { // without reload 	
		window.history.pushState({path:newurl}, null, newurl);
	}
	
};
    
var GetParamUrl = function(_k) {// get parameter by key

	let sPageURL = decodeURIComponent(window.location.search.substr(1)),
		sURLVariables = sPageURL.split('&').map(_v => _v.split('='));
	let _result = sURLVariables.find(_v => _v[0] === _k);
	return _result[1];

};