Skip to main content
All docs
V24.2

The 'Microsoft JScript runtime error: 'X' is undefined' error message appears when the Control.Visible property is set to false

#Error Description

The “Microsoft JScript runtime error: ‘X’ is undefined” error message appears when you try to access a DevExpress ASP.NET control whose Visible property is set to false.

This error occurs because a control is not rendered on a page if its Visible property is set to false. As a result, you cannot access the control on the client.

Note

If a container control is not rendered, nested controls are not rendered either. The individual nested control returns false for the Visible property even if you have explicitly set it to true.

#Solution

Use the ClientVisible property to hide a control on the server and then make it visible on the client.

#See Also

The Difference Between the Enabled / Visible and ClientEnabled / ClientVisible Properties