Adding an onclick event to a table row

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I'm trying to add an onclick event to a table row through Javascript.

function addRowHandlers() {
    var table = document.getElementById("tableId");
    var rows = table.getElementsByTagName("tr");
    for (i = 1; i < rows.length; i++) {
        row = table.rows[i];
        row.onclick = function(){
                          var cell = this.getElementsByTagName("td")[0];
                          var id = cell.innerHTML;
                          alert("id:" + id);
                      };
    }
}

This works as expected in Firefox, but in Internet Explorer (IE8) I can't access the table cells. I believe that is somehow related to the fact that "this" in the onclick function is identified as "Window" instead of "Table" (or something like that).

If I could access the the current row I could perform a getElementById in the onclick function by I can't find a way to do that. Any suggestions?

12 Answers

Something like this.

function addRowHandlers() {
  var table = document.getElementById("tableId");
  var rows = table.getElementsByTagName("tr");
  for (i = 0; i < rows.length; i++) {
    var currentRow = table.rows[i];
    var createClickHandler = function(row) {
      return function() {
        var cell = row.getElementsByTagName("td")[0];
        var id = cell.innerHTML;
        alert("id:" + id);
      };
    };
    currentRow.onclick = createClickHandler(currentRow);
  }
}

EDIT

Working demo.

Simple way is generating code as bellow:

<!DOCTYPE html>
<html>
<head>

<style>
  table, td {
      border:1px solid black;
  }
</style>

</head>
<body>
<p>Click on each tr element to alert its index position in the table:</p>
<table>
  <tr onclick="myFunction(this)">
    <td>Click to show rowIndex</td>
  </tr>
  <tr onclick="myFunction(this)">
    <td>Click to show rowIndex</td>
  </tr>
  <tr onclick="myFunction(this)">
    <td>Click to show rowIndex</td>
  </tr>
</table>

<script>
  function myFunction(x) {
      alert("Row index is: " + x.rowIndex);
  }
</script>

</body>
</html>

I think for IE you will need to use the srcElement property of the Event object. if jQuery is an option for you, you may want to consider using it - as it abstracts most browser differences for you. Example jQuery:

$("#tableId tr").click(function() {
   alert($(this).children("td").html());
});

Head stuck in jq for too long. This will work.

function addRowHandlers() {
    var table = document.getElementById("tableId");
    var rows = table.getElementsByTagName("tr");
    for (i = 1; i < rows.length; i++) {
        var row = table.rows[i];
        row.onclick = function(myrow){
                          return function() { 
                             var cell = myrow.getElementsByTagName("td")[0];
                             var id = cell.innerHTML;
                             alert("id:" + id);
                      };
                  }(row);
    }
}

I try to figure out how to get a better result with pure JS and i get something this:

DEMO: https://jsfiddle.net/f5r3emjt/1/

const tbody = document.getElementById("tbody");
let rowSelected;

tbody.onclick = (e) => {
  for (let i = 0; i < e.path.length; ++i) {
    if (e.path[i].tagName == "TR") {
      selectRow(e.path[i]);
      break;
    }
  }
};

function selectRow(r) {
  if (rowSelected !== undefined) rowSelected.style.backgroundColor = "white";

  rowSelected = r;
  rowSelected.style.backgroundColor = "dodgerblue";
}

And now you can use the variable rowSelected in other function like you want or call another function after set the style

I like more this implementacion and also compatible with any browser

tbody.onclick = (e) => {
 // we need to get the tr element because we always select the td element
 const tr = e.srcElement.parentNode; 
 tr == "TR" && selectRow( tr );
};

Try changing the this.getElementsByTagName("td")[0]) line to read row.getElementsByTagName("td")[0];. That should capture the row reference in a closure, and it should work as expected.

Edit: The above is wrong, since row is a global variable -- as others have said, allocate a new variable and then use THAT in the closure.

My table is in another iframe so i modified SolutionYogi answer to work with that:

<script type="text/javascript">
window.onload = addRowHandlers;
function addRowHandlers() {
    var iframe = document.getElementById('myiframe');
    var innerDoc = (iframe.contentDocument) ? iframe.contentDocument : iframe.contentWindow.document;

    var table = innerDoc.getElementById("mytable");
    var rows = table.getElementsByTagName("tr");
    for (i = 0; i < rows.length; i++) {
        var currentRow = table.rows[i];
        var createClickHandler = 
            function(row) 
            {
                return function() { 
                                        var cell = row.getElementsByTagName("td")[0];
                                        var id = cell.innerHTML;
                                        alert("id:" + id);
                                 };
            }

        currentRow.onclick = createClickHandler(currentRow);
    }
}
</script>

While most answers are a copy of SolutionYogi's answer, they all miss an important check to see if 'cell' is not null which will return an error if clicking on the headers. So, here is the answer with the check included:

function addRowHandlers() {
  var table = document.getElementById("tableId");
  var rows = table.getElementsByTagName("tr");
  for (i = 0; i < rows.length; i++) {
    var currentRow = table.rows[i];
    var createClickHandler = function(row) {
      return function() {
        var cell = row.getElementsByTagName("td")[0];
        // check if not null
        if(!cell) return; // no errors! 
        var id = cell.innerHTML;
        alert("id:" + id);
      };
    };
    currentRow.onclick = createClickHandler(currentRow);
  }
}
selectRowToInput();
function selectRowToInput(){
var table = document.getElementById("table");
var rows = table.getElementsByTagName("tr");
for (var i = 0; i < rows.length; i++)
{
    var currentRow = table.rows[i];
    currentRow.onclick = function() {

       rows=this.rowIndex;
        console.log(rows);  
    };
}

}
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