How to count how many checkboxes has been checked
<p>I have a HTML table first column consists of check boxes etc when the user clicks a button i want to check if any of the check boxes have been checked before going to the code behind etc.</p>

<p>This is what i have but it keeps throwing an error 
"Microsoft JScript runtime error: Syntax error, unrecognized expression: input.checkbox:checked"]"</p>

<p>This is my code i just want to return the count of how many checkboxes are actually checked.
<code></p>

<pre><code>   $('#BtnExportToExcel').click(function () {
          var check = ('#gvPerformanceResult').find('input.checkbox:checked"]').length;
          alert(check);
    return false;
    }):
</code></pre>

<p></code></p>

<p>Thanks for your help.</p>
