How to disable input text while the radio button is checked in javascript? : <label for="position"><b>Position:</b></label><br/><br/>
<input type="radio" name="position" id="r1" value="Dean" />Dean
<input type="radio" name="position" id="r2" value="Instructor"/>Instructor
<input type="radio" name="position" id="r3" value="Student"/>Student<br/><br/>
<input type="radio" name="position" id ="r4" value="<?php echo $_POST['otherPosition']?>"/>
Others:
<input type="text"  value = "<?php if($error==TRUE){echo $_POST['otherPosition'];}?>" id="otherPosition" placeholder="Specify" name="position"/>