Widget Admin – Form Submit Event?

You need to listen for the click event (there is no such thing as a pre/before click) and do some work right then or figure out if you want to allow the click to “go through” or not based on some validation for example.

jQuery(function($) {
    // We are binding to the body so that the code
    // will work for future elements added to the DOM
    $('body').on('click', '.widget-control-save', function(ev) {
        var my_validation = true;

        if ( my_validation ) {
            console.log('widget save!');
        } else {
            ev.preventDefault();
            ev.stopPropagation(); /* We are capturing the event so it won't bubble up. */
        }
    })
});