Unless you want to refresh the page or have a 'send to all' checkbox that doesn't select all the other checkboxes for you, that's a javascript thing. Set an onclick for the checkbox that controls them all that goes and selects the rest.

function toggleAll()

{

   for(var i=0; i<document.myform.elements.length; i++)

      document.myform.elements(i).checked=document.myform.tog.checked;

}

The BBS markup is being a nuisance - the (i) above should be square brackets.HTML for the master toggle checkbox:

<input type=checkbox name=tog onclick="javascript:toggleAll();">