when using time or tree components in input (* required fields), some components will be available for input. If you use readonly, and add required, you will have the problem of verifying required fields and not filling them without prompts.
< hr >< label class= "col-sm-2 control-label" > finish date: < / label >
< div class= "col-sm-4" >
< input type= "text" id= "date_end" class= "form-control" required= "required" readonly >
< / div >