Filter single colum in table javascript

 function searchTable() {
            var input, filter, table, tr, td, i, txtValue;
            input = document.getElementById("txt-search-patient");
            filter = input.value.toUpperCase();
            table = document.getElementById("tbl-patient");
            tr = table.getElementsByTagName("tr");
            for (i = 0; i < tr.length; i++) {
                td = tr[i].getElementsByTagName("td")[0];
                if (td) {
                    txtValue = td.textContent || td.innerText;
                    if (txtValue.toUpperCase().indexOf(filter) > -1) {
                        tr[i].style.display = "";
                    } else {
                        tr[i].style.display = "none";
                    }
                }
            }
        }