Scrollview ScrollToBottom

I've got the below bit of code:

function doFocus(){
    $.toolbar.bottom = 216;
    $.scrollview.bottom = 256;
    $.scrollview.scrollToBottom();
}

However the $.scrollview.scrollToBottom(); does not appear to do anything. What i want it to do is when the text area is selected i want the scrollview to scroll to the bottom of where the content is