dojo dijit.form.timetextbox disabled but value still present

dojo dijit.form.timetextbox disabled but value still present

I want to have my dojo dijit.form.timetextbox disabled but the last set
value still displayed.
If I set the disabled attr to true the field is disabled but the value is
gone. Is there any other way?
dijit.byId('form_endtime').set('disabled', true);
I am using Dojo 1.6