You can use .scrollIntoView() for this. It will bring a specific element into the viewport.
Example:
document.getElementById( 'bottom' ).scrollIntoView();
Demo: http://jsfiddle.net/ThinkingStiff/DG8yR/
Script:
function top() {
document.getElementById( 'top' ).scrollIntoView();
};
function bottom() {
document.getElementById( 'bottom' ).scrollIntoView();
window.setTimeout( function () { top(); }, 2000 );
};
bottom();
HTML:
<div id="top">top</div>
<div id="bottom">bottom</div>
CSS:
#top {
border: 1px solid black;
height: 3000px;
}
#bottom {
border: 1px solid red;
}