I am trying to obtain the ClientId of a textbox to concatenate into a javascript function call

When I call:   txtTemp.ClientID    it is the same as the txtTemp.id property.

Sample Code:

Literal moLiteral = new Literal();
moLiteral.Text = "<script type='text/javascript' src='/js/PopupCalendar.js'></script>";
                           
HyperLink moLink = new HyperLink();
moLink.NavigateUrl = " popupCal('Cal','" + txtTemp.ClientID + "','M/d/yyyy','January,February,March,April,May,June,July,August,September,October,November,December','Sun,Mon,Tue,Wed,Thu,Fri,Sat','Today','Close','Calendar',0);";
container.Controls.Add(moLiteral);
container.Controls.Add(moLink);

txtTemp.ClientID returns   DateAvail

but when i view HTML source the textbox txtTemp actual clientID is dnn_ctr368_ViewRentalProperties_detProperty_DateAvail

which is causing my javascript function not to work.

For those who are not familar I am trying to create popup calendar, and from further research on forms I am aware of : DotNetNuke.Common.Utilities.Calendar.InvokePopupCal(txtTemp) but thats throws a NullreferenceException for me because I believe the control has not been added to page heirarchery.

This txtTemp is being built dynamically using InstansiateIn Container so I believe when DNN is attempting to create the javascript for the control, the control is not found by the API, So that is why I am attempting to create the javascript manually.  However I cannot get the instance of the control name.