Question

How do I write OnClick=”return Foo()” in jquery to prevent the button from submitting while the function is not yet finished. TY

Answer 1

Attach a handler to the click event for your target element, pass your handler the event object as a parameter, and call preventDefault() on the event within your handler. Like so:

$('#mydiv').click(function(e) {
  // do something
  e.preventDefault();
});

For more information see click and the event object at the jQuery API.