How to pass a parameter to a dynamically set JavaScript function?

Question

Ok, I have one JavaScript that creates rows in a table like this:

  function AddRow(text,rowID) {
    var tbl = document.getElementById('tblNotePanel');
    var row = tbl.insertRow(tbl.rows.length);

    var cell = row.insertCell();
    var textNode = document.createTextNode(text);
    cell.id = rowID;
    cell.style.backgroundColor = "gold";

    cell.onclick = clickTest;
    
    cell.appendChild(textNode);
  }

In the above function, I set the cell's onclick function to call another JavaScript function called clickTest. My question is when I assign the onclick event to call clickTest, how do I set parameter information to be sent when the clickTest method is called on the cell's onclick event? Or, how do I access the cell's ID in the clickTest function?

Thanks, Jeff

tvanfosson · Accepted Answer · 2008-11-20 03:52:57Z

39

Try this:

cell.onclick = function() { clickTest(rowID); };

The idea is that you are binding the onclick handler to the anonymous function. The anonymous function calls clickTest with rowID as the parameter.

answered Nov 20, 2008 at 3:52

tvanfosson

534k102 gold badges703 silver badges801 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Eric Schoonover · Accepted Answer · 2008-11-20 03:52:28Z

In the clickTest function you should have access to a the this variable. Try this inside of clickTest function:

alert(this.id);

This will refer to the DOM element that fired the event.

Basically, there isn't really a way to pass parameters to an event handler function. The reason for that is that the browser is executing the function based on an event and you are not actually calling the function.

You can use closures which allow you to access local variables (to the closure) when you assign the event handler function. That would look like this:

cell.onclick = function() { alert(this.id); alert(cell.id); };

Were cell.id is the locally scoped variable that is still considered in scope when the event handler is executed.

ar2015 · Accepted Answer · 2022-09-06 22:01:38Z

1

The suggested solutions work most of the time except for special scenarios.

In case you have a for loop adding onclicks calling another function with different parameters and when testing you realize all your item's behave like the last item, you may consider adding onclick as a text:

for(var loopObj of loopObjList)
    mydiv.setAttribute('onclick', 'javascript: pick_option(' + loopObj.id + ', "' + loopObj.value + '");' );

answered Sep 6, 2022 at 22:01

ar2015

6,24010 gold badges62 silver badges120 bronze badges

Collectives™ on Stack Overflow

How to pass a parameter to a dynamically set JavaScript function?

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related