I ended up doing such… and it works well, I post it here in case someone else wants to do the same…. 
thanks anyway !
My initiating code…
$("#calendarContainerMemes").jqxCalendar({ width: '100%', height: '400px', culture: 'fr-FR', showOtherMonthDays: false, disabled: true, renderedHandler: function(numRendered) {
runCustomLookOnCalendar('calendarContainerMemes');
}
});
Inside render method…
render: function() {
startRendering = new Date().getTime();
if (!this.canRender) {
return
}
this.host.children().remove();
var c = this._renderSingleCalendar("View" + this.element.id);
var b = this;
this.host.append(c)
var end = new Date().getTime();
var time = end - startRendering;
if (this.renderedHandler) {
this.renderedHandler(time)
}
}