Adding a parameter to the URL with JavaScript

Question

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:

Answer 1

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);
            }
        }