JAVASCRIPT

readonly attribute in html by javascript

document.getElementById("yourID").readOnly = true; 

readonly attribute in html

<!--The readonly attribute means that the value of input field is not editable
-->
<form action="">
<label for="country">Language:</label> 
	<input type="text" id="language" name="language" value="English" readonly>
	<input type="submit" value="Submit">
</form>