<!DOCTYPE html>
<html>
<body>
<h3>A demonstration of how to access a Checkbox</h3>
Checkbox: <input type="checkbox" id="myCheck">
<p>Click the "Try it" button to check the checkbox.</p>
<button onclick="myFunction()">Try it</button>
<script>
function myFunction() {
var x = document.getElementById("myCheck");
x.checked = true;
}
</script>
</body>
</html>