You can write a jQuery function like this to determine if an element is in the viewport.
Include this somewhere after jQuery is included:
$.fn.isInViewport = function() {
var elementTop = $(this).offset().top;
var elementBottom = elementTop + $(this).outerHeight();
var viewportTop = $(window).scrollTop();
var viewportBottom = viewportTop + $(window).height();
return elementBottom > viewportTop && elementTop < viewportBottom;
};
Sample usage:
$(window).on('resize scroll', function() {
if ($('#Something').isInViewport()) {
// do something
} else {
// do something else
}
});
Note that this only checks the top and bottom positions of elements, it doesn’t check if an element is outside of the viewport horizontally.