check if element is scrolled into browser view

gistfile1.js

function element_in_scroll(elem) {

    var docViewTop = $(window).scrollTop();
    var docViewBottom = docViewTop + $(window).height();
 
    var elemTop = $(elem).offset().top;
    var elemBottom = elemTop + $(elem).height();
 
    return ((elemBottom <= docViewBottom) && (elemTop >= docViewTop));
}