Submit button on AO's causing duplicate receiving slip lines

[MayrelCerero]

Hello!

I'm working on a way to stop users from accidentally submitting the Receive Purchase Order pop-up more than once, since clicking the submit button multiple times ends up doubling the counts. The submit button isn't a standard UI Action, so I tried using a client script, but no luck so far. Anyone have ideas on how to fix this?

//I have this set on the Asset Order [proc_po] table
function onSubmit() {
    var submitButton = g_form.getControl('sysverb_insert');
    if (submitButton) {
        submitButton.disabled = true;
        return true;
    }
}