Q: Raphael.js function getBBox give back NAN/NAN/NAN in IE8 using Raphaël 2.1.4 - JavaScript Vector Library 
do something like that:
var textDummy = paper.text(50,500, 'hello world').attr({fill: 'transparent', 'font-size': 14});
var textBox = textDummy.getBBox();

with chrome and firefox everything is fine,
but in IE8 it give back NaN/NaN/NaN,
par exemple textBox.height is NaN.
how i can fix this?

A: i found a workaround solution from this answer to the question
"Raphael JS and Text positioning"
If i use _getBBox() instead of getBBox() everything is working in ie 8 also.

_getBBox() is undocumented but used internally by Raphael itself, and it works!


A: I had the same problem in Rapahel 2.2.0 and 2.2.1, and using ._getBBox() didn't fix it for me. 
What did fix it for me is falling back to .auxGetBBox() if it's defined and regular .getBBox() doesn't work, like this:
var bbox = path.getBBox( );

// Workaround for apparent bug in Raphael's VML module's getBBox() override
if( isNaN( bbox.x ) && path.auxGetBBox ){
  bbox = path.auxGetBBox();
}


I don't have a fix for the underlying bug, but I have found the source of it.
In VML mode, Raphael takes the initial getBBox() function, saves it as auxGetBBox() on the element prototype, then replaces it with a function that appears to be broken. 
It has calculations based on a variable defined as var z = 1/this.paper._viewBoxShift.scale;, which clearly expects _viewBoxShift.scale to be some factor of the scale of the current viewbox compared to the initial viewbox , but actually _viewBoxShift.scale is an object like this which appears to come from paperproto.getSize():
{ height: someNumber, width: someNumber }
This is where all the NaNs are coming from. Cannae divide by an object.
So this workaround works fine if no zoom is applied using a viewbox, but may give incorrect results if a zoom has been applied (something I can't get to work at all in recent versions of raphael in VML mode, but that's a seperate question). Fixing that will involve digging deep into Raphael's VML module to pipe a proper zoom factor into this z variable.
