function onVisibilityChange(el, callback) {
var old_visible;
return function () {
var visible = isElementInViewport(el);
if (visible != old_visible) {
old_visible = visible;
if (typeof callback == 'function') {
callback();
}
}
}
}
var handler = onVisibilityChange(el, function() {
/* Your code go here */
});
// jQuery
$(window).on('DOMContentLoaded load resize scroll', handler);
// Non-jQuery
if (window.addEventListener) {
addEventListener('DOMContentLoaded', handler, false);
addEventListener('load', handler, false);
addEventListener('scroll', handler, false);
addEventListener('resize', handler, false);
} else if (window.attachEvent) {
attachEvent('onDOMContentLoaded', handler); // Internet Explorer 9+ :(
attachEvent('onload', handler);
attachEvent('onscroll', handler);
attachEvent('onresize', handler);
}