How can I add or update a query string parameter?

Question

With javascript how can I add a query string parameter to the url if not present or if it present, update the current value? I am using jquery for my client side development

Answer 1

This is my preference, and it covers the cases I can think of. Can anyone think of a way to reduce it to a single replace?

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