paper.localToPageRect(rect)

Transform the rectangle rect defined in local coordinate system to the page coordinate system.

var bbox = element.getBBox();
var pageRect1 = paper.localToPageRect(bbox);
 // alternative method signature
var pageRect2 = paper.localToPageRect(bbox.x, bbox.y, bbox.width, bbox.height);
// Draw an HTML rectangle above the element.
var div = document.createElement('div');
div.style.position = 'absolute';
div.style.background = 'red';
div.style.left = pageRect1.x + 'px';
div.style.top = pageRect1.y + 'px';
div.style.width = pageRect1.width + 'px';
div.style.height = pageRect1.height + 'px';
document.body.appendChild(div);