A Whiteboard with CSS3 Sliding effect and Checkbox based on a Vector Tutsplus Tutorial. The effect is achieved using the checkbox hack where the checkbox is hidden behind the opener by setting its opacity to 0. When the opener / checkbox is clicked or checked, the height of the content area is increased and the checkbox’s position is changed so that it moves with the opener. The animation is achieved by using CSS3’s transition property which isn’t supported by Internet Explorer yet so the demons…