function initBigFrame() 
{

    var anchor, anchors, index, rel;

    if (!document.getElementsByTagName) return;

    anchors = document.getElementsByTagName('a');

    for (index = 0; index < anchors.length; index++) 
    {
        anchor = anchors[index];

        rel = anchor.rel;

        if (rel == 'bigframe')
            anchor.href = 'javascript:showBigFrame(\'' + anchor.href + '\');';
    }
    
    hideBigFrame();
}

function hideBigFrame() 
{
    var objframe = document.getElementById('BigFrame');

    objframe.style.display = 'none';
}

function getViewPort()
{
	var top =
		window.pageYOffset ? window.pageYOffset : 
			document.documentElement.scrollTop ? document.documentElement.scrollTop : document.body.scrollTop;

	var left =
		window.pageXOffset ? window.pageXOffset : 
			document.documentElement.scrollLeft ? document.documentElement.scrollLeft : document.body.scrollLeft;

	var width =
		window.innerWidth || 
		document.documentElement.clientWidth || 
		document.body.clientWidth;

	var height =
		window.innerHeight || 
		document.documentElement.clientHeight || 
		document.body.clientHeight;

	return [top, height, left, width];
	
}


function showBigFrame(src) 
{
    var imgpreload = new Image();

    hideBigFrame();

    imgpreload.onload = function () 
    {

		var viewPortArray = getViewPort();        
		
        var top = viewPortArray[0] + ((viewPortArray[1] - imgpreload.height) / 2);
        var left = viewPortArray[2] + ((viewPortArray[3] - imgpreload.width) /2);

		var objframe = document.getElementById('BigFrame');
		var objpic = document.getElementById('BigPicture');

        objpic.src = src;
        
        objframe.style.top = top + 'px';
        objframe.style.left = left + 'px';

        objframe.style.display = 'block';
    }
	
    imgpreload.src = src;
}