Javascript not working

<script type="text/javascript">
                    function trim(str) {
                        return str.replace(/^\s*/g, '').replace(/\s*$/g, '');
                       
                    }
                    function bvalidate(event) {
                        debugger;
                        var txt1 = document.getElementById("txt1").value;
                        var grid = document.getElementById("GridView1");
//                        var cell;
                        if (txt1 == null || txt1 == "") 
                        {
                            alert("country cannot be empty ")
                            return false;
                        }


                        if (grid != null) 
                        {
                            for (var i = 1; i <= grid.rows.length - 1; i++) 
                            {
//                              cell = grid.rows[i].cells[1].innerText;
                              if (trim(grid.rows[i].cells[1].innerText) == trim(txt1)) {
                                  alert("Item Already Exits")
                                  return false;
                                }
                             
                            }
                            return false;

                        }
                        
                        
                    }
                    
                </script>