如何获得图像的中心标签？

Question

Say I have the following:

document.elementFromPoint(12, 23);

which is an image, how do I figure out the center x and y coordinate of the image? relative-ly from the whole view?

Answer 1

ImageXCenter = ImageXPos + Math.abs( ImageWidth / ImageXPos ) / 2;
ImageYCenter = ImageYPos + Math.abs( ImageHeight / ImageYPos ) / 2;

Answer 2

This should do:

Fiddle: http://jsfiddle.net/9ex2V/

function getCenter (e) {
    var left = e.offsetLeft,
        top = e.offsetTop,
        parent = e;

    while(parent = parent.offsetParent) {
        left += parent.offsetLeft;
        top += parent.offsetTop;  
    }


    return [
      left + Math.floor(e.offsetWidth / 2),
      top + Math.floor(e.offsetHeight / 2) 
    ];
}

Hope I haven't overlooked anything about html/body/anything border/margin/padding.