iOS/WebKit: touchmove/touchstart not working on input & textarea

I have an IOS Web App that can't be scrolled. For that reason I want to deactivate scrolling. To do this, I use an element's ontouchmove attribute and have it call a function that uses element.preventDefault. However, I am unable to detect any touching event when it starts on a textarea or input element, even when the element is disabled! I have also tried binding the touchmove or touchstart event to these elements via JavaScript's addEventlistener, without success!

And here's my JavaScript:

function onBodyLoad() {

 document.addEventListener( "touchstart", doNotScroll, true );
 document.addEventListener( "touchmove", doNotScroll, true );

}

function doNotScroll( event ) {

 event.preventDefault();
 event.stopPropagation();

}

Thanks for any help!