javascript - Retrieve width/height of a css3 scaled element -

i'm fighting against oddity (i think) of offsetwidth property.
scenario:

i've got, let's say, span tag, in js, @ point perform css3 transform element, like:

        el.set('styles', {             'transform':'scale('+scale+', '+scale+')',      /* things in normal world */             '-ms-transform':'scale('+scale+', '+scale+')',      /* ie 9 */             '-moz-transform':'scale('+scale+', '+scale+')',         /* moz */             '-webkit-transform':'scale('+scale+', '+scale+')',  /* safari / chrome */             '-o-transform':'scale('+scale+')'       /* oprah winfrey */          });          w = el.getwidth();         console.log('after scaling: ' + w); 

at point log returns me fuzzy values, doesn't know say.
suggestion?

getboundingclientrect() returns correct values me.

jsfiddle.