javascript - How to get the value from the GET parameters?

Question

I have a URL with some GET parameters as follows:

www.test.com/t.html?a=1&b=3&c=m2-m3-m4-m5 

I need to get the whole value of c. I tried to read the URL, but I got only m2. How do I do this using JavaScript?

Answer 1

JavaScript itself has nothing built in for handling query string parameters.

Code running in a (modern) browser you can use the URL object (which is part of the APIs provided by browsers to JS):

var url_string = "http://www.example.com/t.html?a=1&b=3&c=m2-m3-m4-m5"; //window.location.href
var url = new URL(url_string);
var c = url.searchParams.get("c");
console.log(c);

---

For older browsers (including Internet Explorer), you can use this polyfill or the code from the original version of this answer that predates URL:

You could access location.search, which would give you from the ? character on to the end of the URL or the start of the fragment identifier (#foo), whichever comes first.

Then you can parse it with this:

function parse_query_string(query) {
  var vars = query.split("&");
  var query_string = {};
  for (var i = 0; i < vars.length; i++) {
    var pair = vars[i].split("=");
    var key = decodeURIComponent(pair[0]);
    var value = decodeURIComponent(pair[1]);
    // If first entry with this name
    if (typeof query_string[key] === "undefined") {
      query_string[key] = decodeURIComponent(value);
      // If second entry with this name
    } else if (typeof query_string[key] === "string") {
      var arr = [query_string[key], decodeURIComponent(value)];
      query_string[key] = arr;
      // If third or later entry with this name
    } else {
      query_string[key].push(decodeURIComponent(value));
    }
  }
  return query_string;
}

var query_string = "a=1&b=3&c=m2-m3-m4-m5";
var parsed_qs = parse_query_string(query_string);
console.log(parsed_qs.c);

You can get the query string from the URL of the current page with:

var query = window.location.search.substring(1);
var qs = parse_query_string(query);

Answer 2

Most implementations I've seen miss out URL-decoding the names and the values.

Here's a general utility function that also does proper URL-decoding:

function getQueryParams(qs) {
    qs = qs.split('+').join(' ');

    var params = {},
        tokens,
        re = /[?&]?([^=]+)=([^&]*)/g;

    while (tokens = re.exec(qs)) {
        params[decodeURIComponent(tokens[1])] = decodeURIComponent(tokens[2]);
    }

    return params;
}

//var query = getQueryParams(document.location.search);
//alert(query.foo);

Answer 3

source

function gup( name, url ) {
    if (!url) url = location.href;
    name = name.replace(/[\[]/,"\\\[").replace(/[\]]/,"\\\]");
    var regexS = "[\\?&]"+name+"=([^&#]*)";
    var regex = new RegExp( regexS );
    var results = regex.exec( url );
    return results == null ? null : results[1];
}
gup('q', 'hxxp://example.com/?q=abc')

Answer 4

This is an easy way to check just one parameter:

Example URL:

http://myserver/action?myParam=2

Example Javascript:

var myParam = location.search.split('myParam=')[1]

if "myParam" exists in the URL... variable myParam will contain "2", otherwise it will be undefined.

Maybe you want a default value, in that case:

var myParam = location.search.split('myParam=')[1] ? location.search.split('myParam=')[1] : 'myDefaultValue';

Update: This works better:

var url = "http://www.example.com/index.php?myParam=384&login=admin"; // or window.location.href for current url
var captured = /myParam=([^&]+)/.exec(url)[1]; // Value is in [1] ('384' in our case)
var result = captured ? captured : 'myDefaultValue';

And it works right even when URL is full of parameters.

Answer 5

Browsers vendors have implemented a native way to do this via URL and URLSearchParams.

let url = new URL('http://www.test.com/t.html?a=1&b=3&c=m2-m3-m4-m5');
let searchParams = new URLSearchParams(url.search);
console.log(searchParams.get('c'));  // outputs "m2-m3-m4-m5"

Currently supported in Firefox, Opera, Safari, Chrome and Edge. For a list of browser support see here.

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

https://url.spec.whatwg.org/

Eric Bidelman, an engineer at Google, recommends using this polyfill for unsupported browsers.

Answer 6

I found this ages ago, very easy:

function getUrlVars() {
    var vars = {};
    var parts = window.location.href.replace(/[?&]+([^=&]+)=([^&]*)/gi,    
    function(m,key,value) {
      vars[key] = value;
    });
    return vars;
  }

Then call it like this:

var fType = getUrlVars()["type"];

Answer 7

You can get the query string in location.search, then you can split everything after the question mark:

var params = {};

if (location.search) {
    var parts = location.search.substring(1).split('&');

    for (var i = 0; i < parts.length; i++) {
        var nv = parts[i].split('=');
        if (!nv[0]) continue;
        params[nv[0]] = nv[1] || true;
    }
}

// Now you can get the parameters you want like so:
var abc = params.abc;

Answer 8

A super simple way using URLSearchParams.

function getParam(param){
  return new URLSearchParams(window.location.search).get(param);
}

It's currently supported in Chrome, Firefox, Safari, Edge, and others.

Answer 9

I wrote a more simple and elegant solution.

var arr = document.URL.match(/room=([0-9]+)/)
var room = arr[1];

Answer 10

Here is a recursive solution that has no regex, and has minimal mutation (only the params object is mutated, which I believe is unavoidable in JS).

It's awesome because it:

• Is recursive
• Handles multiple parameters of the same name
• Deals well with malformed parameter strings (missing values, so on)
• Doesn't break if '=' is in the value
• Performs URL decoding
• And lastly, It's awesome because it...argh!!!

Code:

var get_params = function(search_string) {

  var parse = function(params, pairs) {
    var pair = pairs[0];
    var parts = pair.split('=');
    var key = decodeURIComponent(parts[0]);
    var value = decodeURIComponent(parts.slice(1).join('='));

    // Handle multiple parameters of the same name
    if (typeof params[key] === "undefined") {
      params[key] = value;
    } else {
      params[key] = [].concat(params[key], value);
    }

    return pairs.length == 1 ? params : parse(params, pairs.slice(1))
  }

  // Get rid of leading ?
  return search_string.length == 0 ? {} : parse({}, search_string.substr(1).split('&'));
}

var params = get_params(location.search);

// Finally, to get the param you want
params['c'];

Answer 11

I made a function that does this:

var getUrlParams = function (url) {
  var params = {};
  (url + '?').split('?')[1].split('&').forEach(function (pair) {
    pair = (pair + '=').split('=').map(decodeURIComponent);
    if (pair[0].length) {
      params[pair[0]] = pair[1];
    }
  });
  return params;
};

Update 5/26/2017, here is an ES7 implementation (runs with babel preset stage 0, 1, 2, or 3):

const getUrlParams = url => `${url}?`.split('?')[1]
  .split('&').reduce((params, pair) =>
    ((key, val) => key ? {...params, [key]: val} : params)
    (...`${pair}=`.split('=').map(decodeURIComponent)), {});

Some tests:

console.log(getUrlParams('https://google.com/foo?a=1&b=2&c')); // Will log {a: '1', b: '2', c: ''}
console.log(getUrlParams('/foo?a=1&b=2&c')); // Will log {a: '1', b: '2', c: ''}
console.log(getUrlParams('?a=1&b=2&c')); // Will log {a: '1', b: '2', c: ''}
console.log(getUrlParams('https://google.com/')); // Will log {}
console.log(getUrlParams('a=1&b=2&c')); // Will log {}

Update 3/26/2018, here is a Typescript implementation:

const getUrlParams = (search: string) => `${search}?`
  .split('?')[1]
  .split('&')
  .reduce(
    (params: object, pair: string) => {
      const [key, value] = `${pair}=`
        .split('=')
        .map(decodeURIComponent)

      return key.length > 0 ? { ...params, [key]: value } : params
    },
    {}
  )

Update 2/13/2019, here is an updated TypeScript implementation that works with TypeScript 3.

interface IParams { [key: string]: string }

const paramReducer = (params: IParams, pair: string): IParams => {
  const [key, value] = `${pair}=`.split('=').map(decodeURIComponent)

  return key.length > 0 ? { ...params, [key]: value } : params
}

const getUrlParams = (search: string): IParams =>
  `${search}?`.split('?')[1].split('&').reduce<IParams>(paramReducer, {})

Answer 12

See this

function getURLParameters(paramName)
{
    var sURL = window.document.URL.toString();
    if (sURL.indexOf("?") > 0)
    {
        var arrParams = sURL.split("?");
        var arrURLParams = arrParams[1].split("&");
        var arrParamNames = new Array(arrURLParams.length);
        var arrParamValues = new Array(arrURLParams.length);

        var i = 0;
        for (i = 0; i<arrURLParams.length; i++)
        {
            var sParam =  arrURLParams[i].split("=");
            arrParamNames[i] = sParam[0];
            if (sParam[1] != "")
                arrParamValues[i] = unescape(sParam[1]);
            else
                arrParamValues[i] = "No Value";
        }

        for (i=0; i<arrURLParams.length; i++)
        {
            if (arrParamNames[i] == paramName)
            {
                //alert("Parameter:" + arrParamValues[i]);
                return arrParamValues[i];
            }
        }
        return "No Parameters Found";
    }
}

Answer 13

ECMAScript 6 solution:

var params = window.location.search
  .substring(1)
  .split("&")
  .map(v => v.split("="))
  .reduce((map, [key, value]) => map.set(key, decodeURIComponent(value)), new Map())

Answer 14

I use the parseUri library. It allows you to do exactly what you are asking for:

var uri = 'www.test.com/t.html&a=1&b=3&c=m2-m3-m4-m5';
var c = uri.queryKey['c'];
// c = 'm2-m3-m4-m5'

Answer 15

The shortest way:

new URL(location.href).searchParams.get("my_key");

Answer 16

I use

function getVal(str) {
    var v = window.location.search.match(new RegExp('(?:[\?\&]'+str+'=)([^&]+)'));
    return v ? v[1] : null;
}

Answer 17

this question has too many answers, so i'm adding another one.

/**
 * parses and returns URI query parameters 
 * 
 * @param {string} param parm
 * @param {bool?} asArray if true, returns an array instead of a scalar 
 * @returns {Object|Array} 
 */
function getURIParameter(param, asArray) {
    return document.location.search.substring(1).split('&').reduce(function(p,c) {
        var parts = c.split('=', 2).map(function(param) { return decodeURIComponent(param); });
        if(parts.length == 0 || parts[0] != param) return (p instanceof Array) && !asArray ? null : p;
        return asArray ? p.concat(parts.concat(true)[1]) : parts.concat(true)[1];
    }, []);
}

usage:

getURIParameter("id")  // returns the last id or null if not present
getURIParameter("id", true) // returns an array of all ids

this copes with empty parameters (those keys present without "=value"), exposure of both a scalar and array-based value retrieval API, as well as proper URI component decoding.

Answer 18

Here is my solution. As advised by Andy E while answering this question, it's not good for your script's performance if it's repeatedly building various regex strings, running loops etc just to get a single value. So, I've come up with a simpler script that returns all the GET parameters in a single object. You should call it just once, assign the result to a variable and then, at any point in the future, get any value you want from that variable using the appropriate key. Note that it also takes care of URI decoding (i.e things like %20) and replaces + with a space:

 function getUrlQueryParams(url) {
  var queryString = url.split("?")[1];
  var keyValuePairs = queryString.split("&");
  var keyValue = [];
  var queryParams = {};
  keyValuePairs.forEach(function(pair) {
    keyValue = pair.split("=");
    queryParams[keyValue[0]] = decodeURIComponent(keyValue[1]).replace(/\+/g, " ");
});
  return queryParams;
}

So, here are are a few tests of the script for you to see:

// Query parameters with strings only, no special characters.
var currentParams = getUrlQueryParams("example.com/foo?number=zero");
alert(currentParams["number"]); // Gives "zero".

// For the URL you stated above...
var someParams = getUrlQueryParams("www.test.com/t.html?a=1&b=3&c=m2-m3-m4-m5 ");
alert(someParams["c"]); // Gives "m2-m3-m4-m5".

// For a query params with URI encoding...
var someParams = getUrlQueryParams("www.example.com/t.html?phrase=a%20long%20shot&location=Silicon+Valley%2C+USA");
alert(someParams["phrase"]); // Gives "a long shot".
alert(someParams["location"]); // Gives "Silicon Valley, USA".

Answer 19

Or if you don't want to reinvent the URI parsing wheel use URI.js

To get the value of a parameter named foo:

new URI((''+document.location)).search(true).foo

What that does is

1. Convert document.location to a string (it's an object)
2. Feed that string to URI.js's URI class construtor
3. Invoke the search() function to get the search (query) portion of the url
   (passing true tells it to output an object)
4. Access the foo property on the resulting object to get the value

Here's a fiddle for this.... http://jsfiddle.net/m6tett01/12/

Answer 20

For Single Parameter Value like this index.html?msg=1 use following code,

$(window).load(function(){
    queryString();
});

function queryString()
{
    var queryString = window.location.search.substring(1);
    var varArray = queryString.split("="); //eg. index.html?msg=1

    var param1 = varArray[0];
    var param2 = varArray[1];

}

For All Parameter Value use following Code,

$(window).load(function(){
    queryString();
});

function queryString()
{
    var queryString = window.location.search;
    var varArray = queryString.split("&");
    for (var i=0;i<varArray.length;i++) {
      var param = varArray[i].split("=");
        //parameter-value pair
    }
} 

Answer 21

Here I am posting one example. But it's in jQuery. Hope it will help others:

<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript" src="jquery.url.js"></script>

<!-- URL:  www.example.com/correct/?message=done&year=1990-->

<script type="text/javascript">
$(function(){
    $.url.attr('protocol')  // --> Protocol: "http"
    $.url.attr('path')          // --> host: "www.example.com"
    $.url.attr('query')         // --> path: "/correct/"
    $.url.attr('message')   // --> query: "done"
    $.url.attr('year')      // --> query: "1990"
});
</script>

Answer 22

The easiest way using the replace() method:

From the urlStr string:

paramVal = urlStr.replace(/.*param_name=([^&]*).*|(.*)/, '$1');

or from the current URL:

paramVal = document.URL.replace(/.*param_name=([^&]*).*|(.*)/, '$1');

Explanation:

• document.URL - interface returns the document location (page url) as a string.
• replace() - method returns a new string with some or all matches of a pattern replaced by a replacement.
• /.*param_name=([^&]*).*/ - the regular expression pattern enclosed between slashes which means:
  • .* - zero or more of any characters,
  • param_name= - param name which is serched,
  • () - group in regular expression,
  • [^&]* - one or more of any characters excluding &,
  • | - alternation,
  • $1 - reference to first group in regular expression.

var urlStr = 'www.test.com/t.html?a=1&b=3&c=m2-m3-m4-m5';
var c = urlStr.replace(/.*c=([^&]*).*|(.*)/, '$1');
var notExisted = urlStr.replace(/.*not_existed=([^&]*).*|(.*)/, '$1');
console.log(`c === '${c}'`);
console.log(`notExisted === '${notExisted}'`);

Answer 23

Yet another suggestion.

There are some good answers already, but I found them needlessly complex and hard to understand. This is short, simple, and returns a simple associative array with key names corresponding to the token names in the URL.

I added a version with comments below for those who want to learn.

Note this relies on jQuery ($.each) for its loop, which I recommend instead of forEach. I find it simpler to ensure cross-browser compatibility using jQuery across the board rather than plugging in individual fixes to support whichever new functions aren't supported in older browsers.

Edit: After I wrote this I noticed Eric Elliott's answer, which is almost the same, though it uses forEach, while I'm generally against (for reasons stated above).

function getTokens(){
    var tokens = [];
    var query = location.search;
    query = query.slice(1);
    query = query.split('&');
    $.each(query, function(i,value){    
        var token = value.split('=');   
        var key = decodeURIComponent(token[0]);     
        var data = decodeURIComponent(token[1]);
        tokens[key] = data;
    });
    return tokens;
}

Commented version:

function getTokens(){
    var tokens = [];            // new array to hold result
    var query = location.search; // everything from the '?' onward 
    query = query.slice(1);     // remove the first character, which will be the '?' 
    query = query.split('&');   // split via each '&', leaving us an array of something=something strings

    // iterate through each something=something string
    $.each(query, function(i,value){    

        // split the something=something string via '=', creating an array containing the token name and data
        var token = value.split('=');   

        // assign the first array element (the token name) to the 'key' variable
        var key = decodeURIComponent(token[0]);     

        // assign the second array element (the token data) to the 'data' variable
        var data = decodeURIComponent(token[1]);

        tokens[key] = data;     // add an associative key/data pair to our result array, with key names being the URI token names
    });

    return tokens;  // return the array
}

For the examples below we'll assume this address:

http://www.example.com/page.htm?id=4&name=murray

You can assign the URL tokens to your own variable:

var tokens = getTokens();

Then refer to each URL token by name like this:

document.write( tokens['id'] );

This would print "4".

You can also simply refer to a a token name from the function directly:

document.write( getTokens()['name'] );

...which would print "murray".

Answer 24

I had the need to read a URL GET variable and complete an action based on the url parameter. I searched high and low for a solution and came across this little piece of code. It basically reads the current page url, perform some regular expression on the URL then saves the url parameters in an associative array, which we can easily access.

So as an example if we had the following url with the javascript at the bottom in place.

http://TestServer/Pages/NewsArchive.aspx?year=2013&Month=July

All we’d need to do to get the parameters id and page are to call this:

The Code will be:

<script type="text/javascript">
var first = getUrlVars()["year"];
var second = getUrlVars()["Month"];

alert(first);
alert(second);
function getUrlVars() {
var vars = {};
var parts = window.location.href.replace(/[?&]+([^=&]+)=([^&]*)/gi, function(m,key,value) {
vars[key] = value;
});
return vars;
}
</script>

Answer 25

// Read a page's GET URL variables and return them as an associative array.
function getUrlVars()
{
    var vars = [], hash;
    var hashes = window.location.href.slice(window.location.href.indexOf('?') + 1).split('&');
    for(var i = 0; i < hashes.length; i++)
    {
        hash = hashes[i].split('=');
        vars.push(hash[0]);
        vars[hash[0]] = hash[1];
    }
    return vars;
}

// Usage for URL: http://my.site.com/location?locationId=53cc272c0364aefcb78756cd&shared=false
var id = getUrlVars()["locationId"];

Got from here: http://jquery-howto.blogspot.ru/2009/09/get-url-parameters-values-with-jquery.html

Answer 26

Simple way

function getParams(url){
        var regex = /[?&]([^=#]+)=([^&#]*)/g,
            params = {},
            match;
        while(match = regex.exec(url)) {
            params[match[1]] = match[2];
        }
        return params;
    }

then call it like getParams(url)

Answer 27

Elegant, functional style solution

Let's create an object containing URL param names as keys, then we can easily extract the parameter by its name:

// URL: https://example.com/?test=true&orderId=9381  

// Build an object containing key-value pairs
export const queryStringParams = window.location.search
  .split('?')[1]
  .split('&')
  .map(keyValue => keyValue.split('='))
  .reduce<QueryStringParams>((params, [key, value]) => {
    params[key] = value;
    return params;
  }, {});

type QueryStringParams = {
  [key: string]: string;
};


// Return URL parameter called "orderId"
return queryStringParams.orderId;

Answer 28

// http:localhost:8080/path?param_1=a&param_2=b
var getParamsMap = function () {
    var params = window.location.search.split("&");
    var paramsMap = {};
    params.forEach(function (p) {
        var v = p.split("=");
        paramsMap[v[0]]=decodeURIComponent(v[1]);
    });
    return paramsMap;
};

// -----------------------

console.log(getParamsMap()["param_1"]);  // should log "a"     

Answer 29

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;
}

// DEMO
console.log(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"));

See also this Fiddle.

Answer 30

Here is what I do:

var uriParams = getSearchParameters();
alert(uriParams.c);


// background functions:

// 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;
}