"

From 2014.igem.org

$(function() {

   var moveLeft = 0;
   var moveDown = 0;
   $('a.popper').hover(function(e) {
  
       var target = '#' + ($(this).attr('data-popbox'));
        
       $(target).show();
       moveLeft = $(this).outerWidth();
       moveDown = ($(target).outerHeight() / 2);
   }, function() {
       var target = '#' + ($(this).attr('data-popbox'));
       $(target).hide();
   });

   $('a.popper').mousemove(function(e) {
       var target = '#' + ($(this).attr('data-popbox'));
        
       leftD = e.pageX + parseInt(moveLeft);
       maxRight = leftD + $(target).outerWidth();
       windowLeft = $(window).width() - 40;
       windowRight = 0;
       maxLeft = e.pageX - (parseInt(moveLeft) + $(target).outerWidth() + 20);
        
       if(maxRight > windowLeft && maxLeft > windowRight)
       {
           leftD = maxLeft;
       }
    
       topD = e.pageY - parseInt(moveDown);
       maxBottom = parseInt(e.pageY + parseInt(moveDown) + 20);
       windowBottom = parseInt(parseInt($(document).scrollTop()) + parseInt($(window).height()));
       maxTop = topD;
       windowTop = parseInt($(document).scrollTop());
       if(maxBottom > windowBottom)
       {
           topD = windowBottom - $(target).outerHeight() - 20;
       } else if(maxTop < windowTop){
           topD = windowTop + 20;
       }
    
       $(target).css('top', topD).css('left', leftD);
    
    
   });

});