<!DOCTYPE html>
<html lang="en-US">
<body>
<input type="text" value="Change Me">
<p>Click on the button to toggle attribute between editable and readonly</p>
<button onclick="myFunction()">Toggle Button</button>
<script>
var elem = document.getElementsByTagName("input")[0];
function myFunction(){
elem.toggleAttribute("readonly");
}
</script> </body>
</html>