How to obtain the query string from the current URL with JavaScript?

Question

Have a look at the MDN article about window.location.

The QueryString is available in window.location.search.

If you want a more convenient interface to work with, you can use the searchParams property of the URL interface, which returns a URLSearchParams object. The returned object has a number of convenient methods, including a get-method. So the equivalent of the above example would be:

let params = (new URL(document.location)).searchParams;
let name = params.get("name");

The URLSearchParams interface can also be used to parse strings in a querystring format, and turn them into a handy URLSearchParams object.

let paramsString = "name=foo&age=1337"
let searchParams = new URLSearchParams(paramsString);

searchParams.has("name") === true; // true
searchParams.get("age") === "1337"; // true

The URLSearchParams interface is now widely adopted in browsers (95%+ according to Can I Use), but if you do need to support legacy browsers as well, you can use a polyfill.

Use window.location.search to get everything after ? including ?

Example:

var url = window.location.search;
url = url.replace("?", ''); // remove the ?
alert(url); //alerts ProjectID=462 is your case

decodeURI(window.location.search)
  .replace('?', '')
  .split('&')
  .map(param => param.split('='))
  .reduce((values, [ key, value ]) => {
    values[ key ] = value
    return values
  }, {})

If you happened to use Typescript and have dom in your the lib of tsconfig.json, you can do:

const url: URL = new URL(window.location.href);
const params: URLSearchParams = url.searchParams;
// get target key/value from URLSearchParams object
const yourParamValue: string = params.get('yourParamKey');

// To append, you can also leverage api to avoid the `?` check 
params.append('newKey', 'newValue');

This will add a global function to access to the queryString variables as a map.

// -------------------------------------------------------------------------------------
// Add function for 'window.location.query( [queryString] )' which returns an object
// of querystring keys and their values. An optional string parameter can be used as
// an alternative to 'window.location.search'.
// -------------------------------------------------------------------------------------
// Add function for 'window.location.query.makeString( object, [addQuestionMark] )'
// which returns a queryString from an object. An optional boolean parameter can be
// used to toggle a leading question mark.
// -------------------------------------------------------------------------------------
if (!window.location.query) {
    window.location.query = function (source) {
        var map = {};
        source = source || this.search;

        if ("" != source) {
            var groups = source, i;

            if (groups.indexOf("?") == 0) {
                groups = groups.substr(1);
            }

            groups = groups.split("&");

            for (i in groups) {
                source = groups[i].split("=",
                    // For: xxx=, Prevents: [xxx, ""], Forces: [xxx]
                    (groups[i].slice(-1) !== "=") + 1
                );

                // Key
                i = decodeURIComponent(source[0]);

                // Value
                source = source[1];
                source = typeof source === "undefined"
                    ? source
                    : decodeURIComponent(source);

                // Save Duplicate Key
                if (i in map) {
                    if (Object.prototype.toString.call(map[i]) !== "[object Array]") {
                        map[i] = [map[i]];
                    }

                    map[i].push(source);
                }

                // Save New Key
                else {
                    map[i] = source;
                }
            }
        }

        return map;
    }

    window.location.query.makeString = function (source, addQuestionMark) {
        var str = "", i, ii, key;

        if (typeof source == "boolean") {
            addQuestionMark = source;
            source = undefined;
        }

        if (source == undefined) {
            str = window.location.search;
        }
        else {
            for (i in source) {
                key = "&" + encodeURIComponent(i);

                if (Object.prototype.toString.call(source[i]) !== "[object Array]") {
                    str += key + addUndefindedValue(source[i]);
                }
                else {
                    for (ii = 0; ii < source[i].length; ii++) {
                        str += key + addUndefindedValue(source[i][ii]);
                    }
                }
            }
        }

        return (addQuestionMark === false ? "" : "?") + str.substr(1);
    }

    function addUndefindedValue(source) {
        return typeof source === "undefined"
            ? ""
            : "=" + encodeURIComponent(source);
    }
}

Enjoy.

You can use this for direct find value via params name.

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