Hi,
The key about the control is, you must follow the document to use it. This means:
1. You can not "invent" anything that does not exist in the documentation. For example, dtCtrl.disabled, dtCtrl.value, dtCtrl.visibleDate are all invalid because property "disabled", "value" and "visibleDate" does not exist;
2. You must use all the methods according to the documentation. For example, setSelectedDate is a method, not a property. So you need to use dtCtrl.setSelectedDate(null), instead of of dtCtrl.setSelectedDate = null;
The key is, eo_GetObject returns an object that only supports these methods:
http://www.essentialobjects.com/ViewDoc.aspx?t=JSDoc.Public.Calendar.htmlEverything else that you do not see there would be your own "invention" and it will never work.
"disabled" is not available on the client side DatePicker object. If you wish to disable the DatePicker, you can set disabled to true on DHTML elements (just like what you did with _eo_DatePicker1_popupimg). Please keep in mind that, eo_GetObject and document.getElementById returns completely different things. So you should not mix them together.
Thanks