Question

in http://api.jquery.com/one/ or in facebook they detect when you are at the bottom of the page and fetch more data [whatever they want] to show !

how to do that ?

Answer 1

If your need is to detect the user is at the lowest portion, the following code will work

<div class="test">not at bottom</div>
<div class="test">not at bottom</div>
<div class="test">not at bottom</div>
....
<div class="test">not at bottom</div>
<div class="test">not at bottom</div>

<div id="placeholder">placeholder</div>


$(window).scroll(function check(){
  var top = $("#placeholder").offset().top;
  if($(window).scrollTop() + jQuery(window).height() > top){
      $(".test").each(function(){$(this).html("at bottom")});
  }else{
      $(".test").each(function(){$(this).html("not at bottom")});
  }
});

You can see this at jsFiddle .