title: unknown checkbox problem
body: <p>Ok, consider this problem. I have a list of email addresses and each email address has a checkbox which marks them as valid or not. OK, so the user can go and check/uncheck each one of the email addresses manually or he can click on a button that selects or deselects all the checkboxes. </p>
  
  <p>However, my problem is, when the user clicks on that button that selects/deselects all the checkboxes, how would the program know in what state all the checkboxes are? I mean: </p>
  
  <pre><code>if (all checkboxes are checked)
  {  uncheck all}
  else
  { check all }
  </code></pre>
  
  <p>I cannot just go and take the value of the first row, since:
  1. User may have checked/unchecked it manually
  2. That ID may no longer be present in the db. </p>
  
  <p>Please help me. </p>