issue with select all (ctrl + a) in a modal popup.

Hi,

When a modal popup is opened, I want to select(using Ctrl+ a) only the content present in the modal popup. 

Currently the content behind the modal popup is also getting selected.

I have tried the below methods:

1. using  Jquery focus() method to focus on the panel of the modal popup.

2. C# Focus() method to focus  on the panel of the modal popup.

3. CSS opacity.

The 2nd method works, but when the user clicks on anywhere on the modal popup the focus is lost and content behind the modal popup is getting selected.

Please help me on this.

Regards,

Salman