Launch Phx using ajax

Hi all,
I’m trying to use Phx after an $modx->getChunk($chunk); in ajax call.
I tried to force event by using $modx->invokeEvent(’OnParseDocument’, array()); but nothing to do my phx syntax survive : [+phx:if=`1`:is=`1`:then=`ok`+]
Have you any idea ?

Thanks,
Regards

no answer ?