$(document).scrollTop() always returns 0

问题

I'm simply trying to do something once the scroll position of the page reaches a certain height. However scrollTop() is returning 0 or null no matter how far down I scroll. This is the help function I'm using to check the scrollTop() value:

$('body').click(function(){
    var scrollPost = $(document).scrollTop();
    alert(scrollPost);
});

I've tried attaching scrollTop() to $('body'), $('html') and of course $(window), but nothing changes.

Any ideas?

回答1:

For some reason, removing 'height: 100%' from my html and body tags fixed this issue.

I hope this helps someone else!

回答2:

I had same problem with scroll = 0 in:

document.body.scrollTop

Next time use

document.scrollingElement.scrollTop

Edit 01.06.2018

If you using event then you got object which has document element in target or srcElement. Here is a table showing scroll operation on different browsers.

As you can see Firefox and IE doesn't have srcElement and IE 11 doesn't support scrollingElement.

回答3:

My solution, after trying some of the above and which doesn't involve changing any CSS:

var scroll_top = Math.max( $("html").scrollTop(), $("body").scrollTop() )

This works in up-to-date versions of Chrome, Firefox, IE and Edge.

回答4:

I just have an add-on for those who might make the same mistake as I did. My code was as followed:

var p = $('html,body');
$( ".info" ).text( "scrollTop:" + p.scrollTop() );

This code will work on all browser except for webkits browser such as chrome and safari because the <html> tag always has a scrollTop value of zero or null.

The other browsers ignore it while webkit's browsers don't.

The simplest solutution is just to remove the html tag from your code et Voila:

var p = $('body');
$( ".info" ).text( "scrollTop:" + p.scrollTop() );

回答5:

Removing height: 100%; from html and body tags can resolve the issue.

The reason is that you might have set 100% as value of height property of html and body elements. If you set the height property of html and body elements to 100%, they get height equal to document’s height.

回答6:

had the same problem. scrollTop() works with some block not document or body. To make this method work u should add height and overflow style for your block:

#scrollParag {
    height: 500px;
    overflow-y: auto;
}

And then:

var scrolParag = document.getElementById('scrollParag');
 alert(scrolParag.scrollTop); // works!

回答7:

Scroll Top was always returning 0 for me as well. I was using it for bringing focus to the specific element on a page. I used another approach to do so.

document.getElementById("elementID").scrollIntoView();

Working well for me on mobile, tablet, and desktop.

回答8:

By the way, it seems that you should use

$("body").scrollTop()

instead of

$(".some-class").scrollTop

This is why I am stuck.

来源：https://stackoverflow.com/questions/12788487/document-scrolltop-always-returns-0

标签

javascript

jquery

scrolltop