svg text elements aligned to center

gistfile1.txt

	var centerTextAlign = function($elem) {
		if ($elem.tagName != 'text') return false;
		var bb=$elem.getBBox();
		var x0=bb.x,y0=bb.y;
		$elem.style.setProperty('text-align', 'center');
		$elem.style.setProperty('text-anchor', 'middle');
		bb=$elem.getBBox();
		var x1=bb.x,y1=bb.y;
		// position changed because of alignment alteration
		var offset = x0 - x1;
		// correct position
		var lst=$elem.transform.baseVal;
		var tsf=$svg.createSVGTransform();
		tsf.setTranslate(offset,y0-y1);
		lst.appendItem(tsf);
		lst.consolidate();   
		return true;
	};