jQuery :offscreen / :onscreen params

onoffscreen.js

// This code snippet is from : http://stackoverflow.com/questions/8897289/how-to-check-if-element-is-off-screen
 
  jQuery.expr.filters.onscreen = function(el) {
    return (
      (el.offsetLeft + el.offsetWidth) > 0 
      || (el.offsetTop + el.offsetHeight) > 0
      || (el.offsetLeft > window.innerWidth || el.offsetTop < window.innerHeight)
    );
  };
  
 
 jQuery.expr.filters.offscreen = function(el) {
    return (
      (el.offsetLeft + el.offsetWidth) < 0 
      || (el.offsetTop + el.offsetHeight) < 0
      || (el.offsetLeft > window.innerWidth || el.offsetTop > window.innerHeight)
    );
  };
  
  
  
// returns all elements that are offscreen
//$(':offscreen');

// boolean returned if element is offscreen
//$('div').is(':offscreen');

  
// returns all elements that are onscreen
//$(':onscreen');

// boolean returned if element is onscreen
//$('div').is(':onscreen');