How to retrieve GET parameters from javascript? [duplicate]

How to retrieve GET parameters from javascript? [duplicate]

This question already has an answer here:

How can I get query string values in JavaScript?

73 answers

http://domain.com/page.html?returnurl=%2Fadmin

For js within page.html,how can it retrieve GET parameters?
For the above simple example,func(‘returnurl’) should be /admin
But it should also work for complex querystrngs…

Solutions/Answers:

Solution 1:

With the window.location object. This code gives you GET without the question mark.

window.location.search.substr(1)

From your example it will return returnurl=%2Fadmin

EDIT: I took the liberty of changing Qwerty’s answer, which is really good, and as he pointed I followed exactly what the OP asked:

function findGetParameter(parameterName) {
    var result = null,
        tmp = [];
    location.search
        .substr(1)
        .split("&")
        .forEach(function (item) {
          tmp = item.split("=");
          if (tmp[0] === parameterName) result = decodeURIComponent(tmp[1]);
        });
    return result;
}

I removed the duplicated function execution from his code, replacing it a variable ( tmp ) and also I’ve added decodeURIComponent, exactly as OP asked. I’m not sure if this may or may not be a security issue.

Or otherwise with plain for loop, which will work even in IE8:

function findGetParameter(parameterName) {
    var result = null,
        tmp = [];
    var items = location.search.substr(1).split("&");
    for (var index = 0; index < items.length; index++) {
        tmp = items[index].split("=");
        if (tmp[0] === parameterName) result = decodeURIComponent(tmp[1]);
    }
    return result;
}

Solution 2:

window.location.search will return everything from the ? on. This code below will remove the ?, use split to separate into key/value arrays, then assign named properties to the params object:

function getSearchParameters() {
      var prmstr = window.location.search.substr(1);
      return prmstr != null && prmstr != "" ? transformToAssocArray(prmstr) : {};
}

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

var params = getSearchParameters();

You can then get the test parameter from http://myurl.com/?test=1 by calling params.test.

Solution 3:

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

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

This is the simplest solution. It unfortunately does not handle multi-valued keys and encoded characters.

"?a=1&a=%2Fadmin&b=2&c=3&d&e"
> queryDict
a: "%2Fadmin"  //overriden with last value, not decoded.
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&a=%2Fadmin"
> queryDict
a: ["1", "5", "t e x t", "/admin"]
b: ["2"]
c: ["3"]
d: [undefined]
e: [undefined, "http://w3schools.com/my test.asp?name=ståle&car=saab"]


In your example, you would access the value like this:

"?returnurl=%2Fadmin"
> qd.returnurl    // ["/admin"]
> qd['returnurl'] // ["/admin"]
> qd.returnurl[0] // "/admin"

Solution 4:

Hey here is the right answer for 2016:

some = new URLSearchParams("https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8&q=mdn%20query%20string")
var q = some.get('q') // 'mdn query string'
var ie = some.has('ie') // true
some.append('new','here')

console.log(q)
console.log(ie)
console.log(some)

https://developer.mozilla.org/en-US/docs/Web/API/URLSearchParams
https://polyfill.io/v2/docs/features/

Solution 5:

a more fancy way to do it: 🙂

var options = window.location.search.slice(1)
                      .split('&')
                      .reduce(function _reduce (/*Object*/ a, /*String*/ b) {
                        b = b.split('=');
                        a[b[0]] = decodeURIComponent(b[1]);
                        return a;
                      }, {});

Solution 6:

i do it like this (to retrieve a specific get-parameter, here ‘parameterName’):

var parameterValue = decodeURIComponent(window.location.search.match(/(\?|&)parameterName\=([^&]*)/)[2]);