function calculateBgX(oElement) {
return document.body.scrollLeft - getOffsetLeft(oElement);
}
function calculateBgY(oElement) {
return document.body.scrollTop - getOffsetTop(oElement);
}

function getOffsetTop(oElement) {
var iResult= oElement.offsetTop;
while (oElement.offsetParent) {
oElement = oElement.offsetParent;
iResult += oElement.offsetTop;
}
return iResult;
}
function getOffsetLeft(oElement) {
var iResult= oElement.offsetLeft;
while (oElement.offsetParent) {
oElement = oElement.offsetParent;
iResult += oElement.offsetLeft;
}
return iResult;
}