title: How to automatically uncheck checkbox if textbox is filled
body: <p>I've made the checkbox to be  default check.  How can I uncheck the checkbox automatically if certain textfield is filled. I've thinking of using javascript. </p>
  
  <hr>
  
  <p>I tried using this</p>
  
  <pre><code>&lt;input type="text" name="commentID" id="commentID" onkeyup="userTyped('skipID', this)"/&gt;
  &lt;input type="checkbox" name="skipID" value="N" id="skipID" checked="checked"  /&gt;
  </code></pre>
  
  <p>and the javascript</p>
  
  <pre><code>function userTyped(commen, e){
  if(e.value.length &gt; 0){
      document.getElementById(commen).checked=false;
  }else{
      document.getElementById(commen).checked=true;
  }}​
  </code></pre>
  
  <p>It works but how if i have 3 textfield, and  I want the checkbox to be filled only after all textfield is filled.</p>