Working with Query Strings

The QueryString (including the ?) is available in window.location.search.

var url = window.location.search.subString(1);// remove the ?
alert(url);

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