javascript scroll event for iPhone/iPad?

I can't seem to capture the scroll event on an iPad. None of these work, what I am doing wrong?

window.onscroll=myFunction;

document.onscroll=myFunction;

window.attachEvent("scroll",myFunction,false);

document.attachEvent("scroll",myFunction,false);

They all work even on Safari 3 on Windows. Ironically, EVERY browser on the PC supports window.onload= if you don't mind clobbering existing events. But no go on iPad.