if you have jQuery and want to detect if something is totally shown, just use this here

jquery.isTotallyInViewPort.js

function isTotallyInViewPort($entry){
    var windowScrollTop = $(window).scrollTop();
    var windowHeight = $(window).height();
    var windowVisibleBottom = windowScrollTop + windowHeight;
    var entryTop = $entry.offset().top;
    var entryOuterHeight = $entry.outerHeight();
    var entryVisibleBottom = entryTop + entryOuterHeight;
    
    var isInView = windowScrollTop < ( entryTop ) < (windowVisibleBottom);
    if(!isInView) return false;
    
    var isCompleteInView = ( entryVisibleBottom ) < (windowVisibleBottom);
    return isCompleteInView;
}