I try to answer this question a few minutes ago and prepared this example for myself :

<script>

  function trialMethod()

  {

    alert('On Submit Run!'); return true;

  }

  function trialMethod2()

  {

    alert('On Submit Run trialMethod2!'); return true;

  }

</script>



<form id=aspnetForm onsubmit=trialMethod();>

    <input type=submit>

</form>

Why the first unbind doesn't work :

<input type=button id=btnTrial1 value=UNBIND 1 

   onclick=$('#aspnetForm').unbind('submit', trialMethod);>

But this one works for the trialMethod2 method :

<input type=button id=btnTrial2 value=UNBIND 2 

   onclick=$('#aspnetForm').bind('submit', trialMethod2).unbind('submit', trialMethod2);>