If you want to prevent form from submitting overiding click wont be enough. One can submit you form by Ctrl+Enter.
You can do the following http://jsfiddle.net/tarabyte/R5yQq/.
Find the form assuming you know button id.
function getForm(id) { var button = document.getElementById(id); while(button && (button = button.parentNode) && (button.nodeName !== 'FORM')){} return button; }
Add 'submit' event listener.
var form = getForm('cancel'), handler = function(ev){ ev = ev || window.event; if(ev.preventDefault) { //w3c browsers ev.preventDefault(); } else { //IE old ev.returnValue = false; } alert('Custom logic goes here!'); }; if(form) { if(form.addEventListener) { form.addEventListener('submit', handler, false) } else if(form.attachEvent) { form.attachEvent('onsubmit', handler); } }