The event handlers are consistent between the two browsers. To pause the scroll while a user mouses over the scrolling box, we added two event handlers to the scrolling pages, onmouseover and onmouseout (all lower case!). These events are defined for both firstPage and secondPage, as either one of them may be exposed at the canvas container. The definitions for the first page are:

firstPage.onmouseover = stopScrolling;
firstPage.onmouseout = scrollPages;

and similarly for the second page:

secondPage.onmouseover = stopScrolling;
secondPage.onmouseout = scrollPages;

function scrollPages() {
    Gtimer = setInterval("moveUp()", Ginterval)
}

The Gtimer variable stores a pointer to the setInterval() command, which invokes the moveUp() function every Ginterval milliseconds. The event handler of the onmouseout event is the stopScrolling() function which clears the Gtimer pointer and thus cancels the call to the moveUp() function, causing the pages to halt:

function stopScrolling() {
  clearInterval(Gtimer);
}