full height

// Find the full, possible, height of an element (not the actual,
// current, height)
function fullHeight( elem ) {
    // If the element is being displayed, then offsetHeight
    // should do the trick, barring that, getHeight() will work
    if ( getStyle( elem, 'display' ) != 'none' )
        return elem.offsetHeight || getHeight( elem );
 
    // Otherwise, we have to deal with an element with a display
    // of none, so we need to reset its CSS properties to get a more
    // accurate reading
    var old = resetCSS( elem, {
        display: '',
        visibility: 'hidden',
        position: 'absolute'
    });
 
    // Figure out what the full height of the element is, using clientHeight
    // and if that doesn’t work, use getHeight
    var h = elem.clientHeight || getHeight( elem );
 
    // Finally, restore the CSS properties back to what they were
    restoreCSS( elem, old );
 
    // and return the full height of the element
    return h;
}
 
// Find the full, possible, width of an element (not the actual,
// current, width)
function fullWidth( elem ) {
    // If the element is being displayed, then offsetWidth
    // should do the trick, barring that, getWidth() will work
    if ( getStyle( elem, 'display' ) != 'none' )
        return elem.offsetWidth || getWidth( elem );
 
    // Otherwise, we have to deal with an element with a display
    // of none, so we need to reset its CSS properties to get a more
    // accurate reading
    var old = resetCSS( elem, {
        display: '',
        visibility: 'hidden',
        position: 'absolute'
    });
 
    // Figure out what the full width of the element is, using clientWidth
    // and if that doesn’t work, use getWidth
    var w = elem.clientWidth || getWidth( elem );
 
    // Finally, restore the CSS properties back to what they were
    restoreCSS( elem, old );
 
    // and return the full width of the element
    return w;
}
 
// A function used for setting a set of CSS properties, which
// can then be restored back again later
function resetCSS( elem, prop ) {
    var old = {};
 
    // Go through each of the properties
    for ( var i in prop ) {
        // Remember the old property value
        old[ i ] = elem.style[ i ];
 
        // And set the new value
        elem.style[ i ] = prop[i];
    }
 
    // Retun the set of changed values, to be used by restoreCSS
    return old;
}
 
// A function for restoring the side effects of the resetCSS function
function restoreCSS( elem, prop ) {
    // Reset all the properties back to their original values
    for ( var i in prop )
        elem.style[ i ] = prop[ i ];
}