How to find out if an element overflows (with jQuery)?

Question

The layout looks like this:

Basically all I want is to find out if the ELEMENT went outside the PAGE :)

All I know is the page width, which is fixed @ 900 px...

Answer 1

Calculate the element's width, then get its left, finally subtract it to the page's width and you'll get the overflow.

var pageWidth = $(".page").width();
var elementWidth = $(".element").width();
var elementLeft = $(".element").position().left;

if (pageWidth - (elementWidth + elementLeft) < 0) {
  alert("overflow!");
} else {
  alert("doesn't overflow");
}

.page {
  overflow: hidden;
  width: 200px;
  height: 200px;
  position: relative;
  background: black;
}

.element {
  width: 100px;
  height: 100px;
  position: absolute;
  background: blue;
  top: 10px;
  left: 150px;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<div class="page">
  <div class="element">
  </div>
</div>

Example here: http://jsfiddle.net/jackJoe/Q5FdG/

Answer 2

Assuming you have some <div id="elem"></div> on your page, you could tell if it is outside of the viewport like this:

var $elem = $('#elem'),
    top = $elem.offset().top,
    left = $elem.offset().left,
    width = $elem.width(),
    height = $elem.height();

if (left + width > $(window).width()) {
    alert('Off page to the right');
}

if (top + height > $(window).height()) {
    alert('Off page to the bottom');
}