ImageButton event being mis-fired

Hello,
            txtFilter.Attributes.Add("onKeyPress", "javascript:if (event.keyCode == 13) __doPostBack('" + lnkFilter.UniqueID + "','')");I have a page containing two ListViews. The purpose of the first ListView is to display current records in the database and allow users to delete them by clicking an ImageButton. The second ListView is for adding new records to the database and utilizes a filtering feature where search criteria can be typed into a textbox and then a LinkButton can be clicked to perform the filtering. In case the user presses Enter, instead of clicking the LinkButton, I incorporated the following code in the Page_ ...