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

The simplest solution I can think of is this method, which will return the modified URI. I feel like most of you are working way too hard.

function setParam(uri, key, val) {
    return uri
        .replace(new RegExp("([?&]"+key+"(?=[=&#]|$)[^#&]*|(?=#|$))"), "&"+key+"="+encodeURIComponent(val))
        .replace(/^([^?&]+)&/, "$1?");
}