Using inline event-handling is not very efficient, have you considered using jQuery and event delegation?
At the end of your view file;
// Using 'heredoc' here so we don't have to escape quotes
$script = <<< JS
// this will handle click events on any checkbox on the page
$(document).on("click", "input[type='checkbox']", function(){
// or AJAX post here
this.form.submit();
});
JS; // note: must be at the start of the line, no space before JS
// Append the script to the buffer
$this->Js->buffer($script);
And just before the inside your layout (e.g. default.ctp)
// output the JavaScript buffer
echo $this->Js->writeBuffer();