PS: If you inspect the resulting HTML code of your view, you’ll notice that the ID of your start_date field is something like [font=“Courier New”]“ModelName_start_date”[/font]
Think the issue you might be having is the fact that you are using CHtml::activeTextField and not CHtml::TextField, with the activeTextField it will make the Txt Box name and id = ModelName[yourSpecifiedInputName]. where as if you used just the CHtml::TextBox the name and id would be = yourSpecifiedInputName.
you could obviously use the activeTextBox but then you would have to catch the data on the other side a little differently.
hope i understood what you where asking and that this helps a little at least