check box checked javascript

Question

I am trying to set a value in a text box based on whether the checkbox is checked or not The function is attached to onclick of the checkbox This simple thing is not working :(

<div>
MyCheckbox
<input type="checkbox" id="Check1" name="FirstCkName" 
 onclick="testCheckbox(Check1,TextBx1)" />
 </div><br>

 <div>
  CheckBx Text Box
  <input id="TextBx1" name="CheckBxName"  type="text"  /> 
  </div><br>

<script>
function testCheckbox(oCheckbox,oTxtbox)
{

if (oCheckbox.checked == true)
{
    document.getElementById("oTxtbox").value=1;
}
else
{
    document.getElementById("oTxtbox").value="";
}
}
</script>

Link to JSfiddle https://jsfiddle.net/JS_learner/2750639m/30/

Answer 1

Do something like.

 var checkBox = document.getElementById("Check1"); checkBox.addEventListener("click", function(e) { if (e.target.checked) { document.getElementById("TextBx1").value = 1; } else { document.getElementById("TextBx1").value = ""; } });

 <div> MyCheckbox <input type="checkbox" id="Check1" name="FirstCkName" /> </div><br> <div> CheckBx Text Box <input id="TextBx1" name="CheckBxName" type="text" /> </div>

Answer 2

The problem is this line:

onclick="testCheckbox(Check1,TextBx1)"

Here you're inventing your own parameters. That won't Work. The 'click' event is a predefined Mousevent , which will give an 'event' argument.

The ' event.target ' will be the element you clicked.

This is how you should define this eventhandler:

onclick="testCheckbox"

Now you can write your script like this:

function testCheckbox(event) { if (event.target.checked == true) { document.getElementById("oTxtbox").value=1; } else { document.getElementById("oTxtbox").value=""; } }