Disabling all fields in CRM 2013 (Orion)

All am disabling all the fields on the form. Fields except the check boxes are disabling.

Can you help why check boxes are not disabled.

The code is :

function disableFormFields(onOff) {

   Xrm.Page.ui.controls.forEach(function (control, index) {

       if (doesControlHaveAttribute(control)) {

           control.setDisabled(onOff);

       }

   });

}

function doesControlHaveAttribute(control) {

   var controlType = control.getControlType();

   return controlType != "iframe" && controlType != "webresource" && controlType != "subgrid";

}

Why this code is not working fine in CRM 2013. This is working fine in CRM 2011.

Thanks!!!!