How do I determine if a checkbox is checked?

For some reason, my form does not want to get the value of a checkbox... I am not sure if it is my coding or not, but when I try and alert() the value, I get undefined as a result. What do I have wrong?

<head>
  <script>
    var lfckv = document.getElementById("lifecheck").checked
    function exefunction(){
      alert(lfckv);
    }
  </script>
</head>
<body>
  <label><input id="lifecheck" type="checkbox" >Lives</label>
</body>

EDIT

I tried changing it to this

function exefunction() {
    alert(document.getElementById("lifecheck").checked);
}

But now it doesn't even want to execute. What's going wrong?

Solution 1:

Place the var lfckv inside the function. When that line is executed, the body isn't parsed yet and the element "lifecheck" doesn't exist. This works perfectly fine:

function exefunction() {
  var lfckv = document.getElementById("lifecheck").checked;
  alert(lfckv);
}

<label><input id="lifecheck" type="checkbox" >Lives</label>
<button onclick="exefunction()">Check value</button>

Solution 2:

You are trying to read the value of your checkbox before it is loaded. The script runs before the checkbox exists. You need to call your script when the page loads:

<body onload="dosomething()">

Example:

http://jsfiddle.net/jtbowden/6dx6A/

You are also missing a semi-colon after your first assignment.

Solution 3:

You can use this code, it can return true or false:

$(document).ready(function(){
  
  //add selector of your checkbox

  var status=$('#IdSelector')[0].checked;
  
  console.log(status);

});

How do I determine if a checkbox is checked?

Solution 1:

Solution 2:

Solution 3:

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