Some browsers (Safari, Mozilla Phoenix) lie for event.target/event.srcElement element on page.
If you wanna be sure that your source element is some tag (eg <h1>) use this trick:
var el = window.event ? window.event.srcElement : e.target;
while (el.tagName !='H1') el = el.parentNode;
alert('Foundn'+el.id);
Big thanks for this advice to Alshur