Perf Improvement for answer http://stackoverflow.com/questions/20452317/jquery-droppable-iframe-offset

gistfile1.js

// perf improvement for answer http://stackoverflow.com/questions/20452317/jquery-droppable-iframe-offset

var $scrollParent = m[i].element.closest("html,body");
m[i].offset.top -= $scrollParent.scrollTop();
m[i].offset.left -= $scrollParent.scrollLeft();

// iframe positioning 
if (this.current.options.iframeOffset) {
    m[i].offset.top += this.current.options.iframeOffset.top;
    m[i].offset.left += this.current.options.iframeOffset.left;
}