The users would go to our site on an IPad, IE9 and Safari on a Windows machine, click submit of their order. If their connection is slow (by any chance) and especially those using IPad since they might not be on a wifi at the time, they click submit again, and again and again..
Those four times of submission will actually cause 4 submissions on the backend whereas on a normal machine, the submission times aren’t affected as long as the page is loading.
Some suggested to use this.disabled on the anchor of the submit. This solved the problem on IE9 but not on IPad and Safaris.
JQuery Browser Compatibility