javascript - Capturing the "scroll down" event?

Question

I'm designing a very simple web page (HTML only), the only "feature" I want to implement is to do something when the user scrolls down the page, is there a way to capture that "event" somehow?

question from:https://stackoverflow.com/questions/4670834/capturing-the-scroll-down-event

Answer 1

If you don't want to use jQuery (which you might not do for a very simple HTML page), you can accomplish this using regular Javascript:

<script>
function scrollFunction() {
    // do your stuff here;
}

window.onscroll = scrollFunction;
</script>

You mentioned that you wanted to do something when they scroll down the page - the onscroll event fires off scrolling in any direction, in either the x- or y-axis, so your function will be called any time they scroll.

If you really want it to only run your code when they scrolled down the page, you'd need to preserve the previous scroll position to compare against whenever onscroll gets called.