javascript - Filtering table multiple columns

Question

I used w3School code for my page and it works fine but it only filters one column, don’t know how create loops but hopping there is easier solution.

    td = tr[i].getElementsByTagName("td")[0];     

changing here 0 to 1 changes the column, could find anything so tried many different thing but not the programmer have no idea if there any other properties that allows multiple columns, spent so much searching, please help

function myFunction() {
  var input, filter, table, tr, td, i;
  input = document.getElementById("myInput");
  filter = input.value.toUpperCase();
  table = document.getElementById("myTable");
  tr = table.getElementsByTagName("tr");
  for (i = 0; i < tr.length; i++) {
    td = tr[i].getElementsByTagName("td")[0];
    if (td) {
      if (td.innerHTML.toUpperCase().indexOf(filter) > -1) {
        tr[i].style.display = "";
      } else {
        tr[i].style.display = "none";
      }
    }
  }
}

* {
  box-sizing: border-box;
}

#myInput {
  background-image: url('/css/searchicon.png');
  background-position: 10px 10px;
  background-repeat: no-repeat;
  width: 100%;
  font-size: 16px;
  padding: 12px 20px 12px 40px;
  border: 1px solid #ddd;
  margin-bottom: 12px;
}

#myTable {
  border-collapse: collapse;
  width: 100%;
  border: 1px solid #ddd;
  font-size: 18px;
}

#myTable th,
#myTable td {
  text-align: left;
  padding: 12px;
}

#myTable tr {
  border-bottom: 1px solid #ddd;
}

#myTable tr.header,
#myTable tr:hover {
  background-color: #f1f1f1;
}

<h2>My Customers</h2>

<input type="text" id="myInput" onkeyup="myFunction()" placeholder="Search             for names.." title="Type in a name">

<table id="myTable">
  <tr class="header">
    <th style="width:60%;">Name</th>
    <th style="width:40%;">Country</th>
  </tr>
  <tr>
    <td>Alfreds Futterkiste</td>
    <td>Germany</td>
  </tr>
  <tr>
    <td>Berglunds snabbkop</td>
    <td>Sweden</td>
  </tr>
  <tr>
    <td>Island Trading</td>
    <td>UK</td>
  </tr>
  <tr>
    <td>Koniglich Essen</td>
    <td>Germany</td>
  </tr>
  <tr>
    <td>Laughing Bacchus Winecellars</td>
    <td>Canada</td>
  </tr>
  <tr>
    <td>Magazzini Alimentari Riuniti</td>
    <td>Italy</td>
  </tr>
  <tr>
    <td>North/South</td>
    <td>UK</td>
  </tr>
  <tr>
    <td>Paris specialites</td>
    <td>France</td>
  </tr>
</table>

Answer 1

There are significantly better resources on the web than W3 Schools, you really should avoid that website IMO. That being said, you just need to look at tr rather than one of the tds if you want to match the whole row:

function myFunction() {
    var input = document.getElementById("myInput");
    var filter = input.value.toUpperCase();
    var table = document.getElementById("myTable");
    var tr = table.getElementsByTagName("tr");
    for (var i = 0; i < tr.length; i++) {
        if (tr.textContent.toUpperCase().indexOf(filter) > -1) {
            tr[i].style.display = "";
        } else {
            tr[i].style.display = "none";
        }      
    }
}

If you want to filter multiple columns instead of the whole row, just use OR (||) in your condition:

function myFunction() {
    var input = document.getElementById("myInput");
    var filter = input.value.toUpperCase();
    var table = document.getElementById("myTable");
    var tr = table.getElementsByTagName("tr");
    var tds = tr.getElementsByTagName('td');

    for (var i = 0; i < tr.length; i++) {
        var firstCol = tds[0].textContent.toUpperCase();
        var secondCol = tds[1].textContent.toUpperCase();
        if (firstCol.indexOf(filter) > -1 || secondCol.indexOf(filter) > -1) {
            tr[i].style.display = "";
        } else {
            tr[i].style.display = "none";
        }      
    }
}

Some reasons why this tutorial isn't great: you should avoid using innerHTML and should instead use textContent since it's possible that your cells will have HTML and the user could type a tag name when trying to search for visible text and be confused by what is matching. You should give your functions names that indicate what they do (e.g. filterTable instead of myFunction). Additionally, there are easier ways to access table data (e.g. tr.cells). If you add a keyup event listener to #myInput you will not need to lookup that DOM node everytime the function is called. Here is an example:

function filterTable(event) {
    var filter = event.target.value.toUpperCase();
    var rows = document.querySelector("#myTable tbody").rows;
    
    for (var i = 0; i < rows.length; i++) {
        var firstCol = rows[i].cells[0].textContent.toUpperCase();
        var secondCol = rows[i].cells[1].textContent.toUpperCase();
        if (firstCol.indexOf(filter) > -1 || secondCol.indexOf(filter) > -1) {
            rows[i].style.display = "";
        } else {
            rows[i].style.display = "none";
        }      
    }
}

document.querySelector('#myInput').addEventListener('keyup', filterTable, false);

<input id="myInput" type="text" />
<table id="myTable">
 <thead>
  <tr class="header">
    <th style="width:60%;">Name</th>
    <th style="width:40%;">Country</th>
  </tr>
 </thead>
 <tbody>
  <tr>
    <td>Alfreds Futterkiste</td>
    <td>Germany</td>
  </tr>
  <tr>
    <td>Berglunds snabbkop</td>
    <td>Sweden</td>
  </tr>
  <tr>
    <td>Island Trading</td>
    <td>UK</td>
  </tr>
  <tr>
    <td>Koniglich Essen</td>
    <td>Germany</td>
  </tr>
  <tr>
    <td>Laughing Bacchus Winecellars</td>
    <td>Canada</td>
  </tr>
  <tr>
    <td>Magazzini Alimentari Riuniti</td>
    <td>Italy</td>
  </tr>
  <tr>
    <td>North/South</td>
    <td>UK</td>
  </tr>
  <tr>
    <td>Paris specialites</td>
    <td>France</td>
  </tr>
 </tbody>
</table>