atributo readonly em html por javascript
document.getElementById("yourID").readOnly = true;
Mr. Samy
document.getElementById("yourID").readOnly = true; <!-- Using readonly attribute is use to prevent changing of input value. -->
Example:
<input type="text" name="username" value="ankur" readonly><!--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>