This code triggers errors any more (ligne 825 and follow):

// From the awesome hack by Dean Edwards
// http://erik.eae.net/archives/2007/07/27/18.54.15/#comment-102291

// If we're not dealing with a regular pixel number
// but a number that has a weird ending, we need to convert it to pixels
if ( !/^\d+(px)?$/i.test( ret ) && /^\d/.test( ret ) ) {
	// Remember the original values
	var left = style.left, rsLeft = elem.runtimeStyle.left;

	// Put in the new values to get a computed value out
	elem.runtimeStyle.left = elem.currentStyle.left;
	style.left = ret || 0;
	ret = style.pixelLeft + "px";

	// Revert the changed values
	style.left = left;
	elem.runtimeStyle.left = rsLeft;
}

This code does not trigger errors any more:

// From the awesome hack by Dean Edwards
// http://erik.eae.net/archives/2007/07/27/18.54.15/#comment-102291

// If we're not dealing with a regular pixel number
// but a number that has a weird ending, we need to convert it to pixels
if ( !/^\d+(px)?$/i.test( ret ) && /^\d/.test( ret ) ) {
	
	// Remember the original values
	var left = style.left[name], rsLeft = elem.runtimeStyle.left[name];

	// Put in the new values to get a computed value out
	elem.runtimeStyle.left[name] = elem.currentStyle.left[name];
	style.left[name] = ret || 0;
	ret = style.pixelLeft + "px";

	// Revert the changed values
	style.left[name] = left || 0;
	elem.runtimeStyle.left[name] = rsLeft;
}

Not formated version:

// From the awesome hack by Dean Edwards
// http://erik.eae.net/archives/2007/07/27/18.54.15/#comment-102291

// If we're not dealing with a regular pixel number
// but a number that has a weird ending, we need to convert it to pixels
if ( !/^\d+(px)?$/i.test( ret ) && /^\d/.test( ret ) ) {
	
	// Remember the original values
	var left = style[name], rsLeft = elem.runtimeStyle[name];

	// Put in the new values to get a computed value out
	elem.runtimeStyle[name] = elem.currentStyle[name];
	style[name] = ret || 0;
	ret = style.pixelLeft + "px";

	// Revert the changed values
	style[name] = left || 0;
	elem.runtimeStyle[name] = rsLeft;
}