function getScrollerWidth() {
    var scr = null;
    var inn = null;
    var wNoScroll = 0;
    var wScroll = 0;

    // Outer scrolling div
    scr = document.createElement('div');
    scr.style.position = 'absolute';
    scr.style.top = '-1000px';
    scr.style.left = '-1000px';
    scr.style.width = '100px';
    scr.style.height = '50px';
    // Start with no scrollbar
    scr.style.overflow = 'hidden';

    // Inner content div
    inn = document.createElement('div');
    inn.style.width = '100%';
    inn.style.height = '200px';

    // Put the inner div in the scrolling div
    scr.appendChild(inn);
    // Append the scrolling div to the doc
    document.body.appendChild(scr);

    // Width of the inner div sans scrollbar
    wNoScroll = inn.offsetWidth;
    // Add the scrollbar
    scr.style.overflow = 'auto';
    // Width of the inner div width scrollbar
    wScroll = inn.offsetWidth;

    // Remove the scrolling div from the doc
    document.body.removeChild(
        document.body.lastChild);

    // Pixel width of the scroller
    return (wNoScroll - wScroll);
}

//alert(getScrollerWidth());
//alert(document.getElementById("content").offsetHeight);
var visibleheight = 310;
var defaultoffset = 16;
var mi = document.getElementById("mainimage");

if(document.getElementById("content").offsetHeight >= visibleheight){	
	var os = getScrollerWidth();
	if(!os)
		os = defaultoffset;
	mi.style.right = os + "px";
}

mi.style.visibility = "visible";