Morgul

$(".dropdown-toggle").click(function(e) {
    var menu = $(this).next('.dropdown-menu'),
        mousex = e.pageX + 20, //Get X coodrinates
        mousey = e.pageY + 20, //Get Y coordinates
        menuWidth = menu.width(), //Find width of tooltip
        menuHeight = menu.height(), //Find height of tooltip
        menuVisX = $(window).width() - (mousex + menuWidth), //Distance of element from the right edge of viewport
        menuVisY = $(window).height() - (mousey + menuHeight); //Distance of element from the bottom of viewport

    if (menuVisX < 20) { //If tooltip exceeds the X coordinate of viewport