Adding a JavaScript confirmation prompt to a delete command button in an ASP.NET grid view?

Question

So I have an ASP.NET grid view:

Answer 1

This is a javascript for delete confirmation.

 function not_check1()
            {
              var where_to1= confirm("Do you really want to delete this record??");

                                    if (where_to1 == true)
                                        {
                                            return true;
                                        }
                                    else
                                        {
                                            return false;
                                        }
           }

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This is a gridview field from where you call the javascript.