I have a custom module that is altering a webform to add custom submission handling using:
$form['#submit'][]='paymentComplete';
From the time the user clicks the submit button, until the paymentComplete() function completes it takes 2-3 seconds, but the user experience doesn't really indicate what is going on. How can I add some type of 'waiting indicator' that starts right BEFORE the request to execute paymentComplete()?