jQuery : how to determine that a div is scrolled d

问题:

I have a div with defined height, and overflow:scroll;. Its content is too long so scrollbars appear.

Now for the ichy part. Some of its inner HTML strangely appears all the time (to be precise, the footer of a table generated by the tableFilter plugin). I'd like to make this footer disappear when it is not needed (it actually appears out of the containing <div>'s border). I resolved to make it disappear but setting its z-index to -1000. But I want to make it appear when the containing <div> is totally scrolled down.

How can I know the user has scrolled at the bottom ?

---

Using the help from answers below, I used scrollTop attribute but the difference between scrollTop and innerHeight is the size of the scrollbar plus some unidentified delta. A scrollbar is 16 pixels high in most browsers under Windows, but I get a difference of 17 in Firefox and something like 20 in IE, where my <div> content's borders seems to be rendered bigger.

A way (actually two ways...) to compute the scrollbar size has been given there.

回答1:

You need to compare the div height with the scrollTop position and the element height.

$(div).scroll(function(){ 
  if(isScrollBottom()){ 
    //scroll is at the bottom 
    //do something... 
  } 
}); 

function isScrollBottom() { 
  var elementHeight = $(element).height(); 
  var scrollPosition = $(div).height() + $(div).scrollTop(); 
  return (elementHeight == scrollPosition); 
} 

回答2:

You can know if the div is scrolled down by simply doing this:

 if ( div.scrollTop + div.clientHeight == div.scrollHeight ){
 //...
 }

It works on Firefox, Chrome and IE8

回答3:

No jQuery needed to get that info:

element.scrollTop;

In a scroll event of your DIV, use that info to check against the height of the element, if it matches (or is close to matching) do whatever you want.

回答4:

function elementInViewport(el) {
   var listcontent= $(".listContainer")[0].getBoundingClientRect();
   var rect = $(el)[0].getBoundingClientRect();
   return [( rect.top >= 0 && rect.left >= 0 && rect.bottom <=  listcontent.bottom), ( rect.bottom - listcontent.bottom )]
}

回答5:

You just need to use the scrollHeight property of the div instead of height. The function isScrollBottom() which Shaun Humphries wrote previously can be put like this

function isScrollBottom() {
var totalHeight = $("divSelector")[0].scrollHeight;
var scrollPosition = $("divSelector").height() + $("divSelector").scrollTop();
return (totalHeight == scrollPosition);
}

回答6:

This is not limited to divs:

toallyScrolled = element.scrollHeight - element.scrollTop === element.clientHeight;

from MDN Element.scrollHeight. There's also a nice demo on that page.

回答7:

I think, simply

$(this).scrollTop()

would do the trick.