disable checkboxes once the count is 5

Hi,

I have a foreach loop that displays survey testimonials. The user is allowed to pick only 5 testimonials. Is there an easy way to disable the rest of the checkboxes once the selected item is 5? I was trying this in jquery but this is not doing anything. Any help or idea would be greatly appreciated. Thanks!!

<script type="text/javascript">
$(document).ready(function () {
var checkedcount = 0;
$('.chkItems').click(function () {
if (this.checked)
checkedcount++;
else
checkedcount--;
if (checkedcount >= 5)
$('.chkItems:notchecked)').attr("disabled", "disabled");
else
$('.chkItems:notchecked)').removeAttr("disabled");
});
});
</script>

@using (Html.BeginForm())
{
<table width="100%" cellpadding="0" cellspacing="0"
rules="all">
<thead>
<tr>
<td align="center" style="padding: 2px 0 2px 2px;">Select</td>
<td align="center" style="padding: 2px 0 2px 2px;">First Name</td>
<td align="center" style="padding: 2px 0 2px 2px;">Last Name</td>
<td align="center" style="padding: 2px 0 2px 2px;">Testimonial</td>
</tr>
</thead>
@{ var i = 0;
}
@foreach (var testimonials in Model.Testimonials)
{
<tr>
<td style="padding: 2px 0 2px 2px;">
@Html.CheckBox("Testimonials[" + i.ToString() + "].DisplayTestimonials", testimonials.DisplayTestimonials.Value, new { @class = "chkItems" })
@Html.Hidden("Testimonials[" + i.ToString() + "].ResponseId", testimonials.ResponseId.ToString())
</td>
<td style="padding: 2px 0 2px 2px;">@Html.TextBox("Testimonials[" + i.ToString() + "].FirstName", testimonials.FirstName, new { @readonly = "readonly", @class = "TextBoxAsLabel" })</td>
<td style="padding: 2px 0 2px 2px;">@Html.TextBox("Testimonials[" + i.ToString() + "].LastName", testimonials.LastName, new { @readonly = "readonly", @class = "TextBoxAsLabel" })</td>
<td style="padding: 2px 0 2px 2px;">@Html.TextBox("Testimonials[" + i.ToString() + "].Question5Answer", testimonials.Question5Answer.ToString(), new { @readonly = "readonly", @class = "TextBoxAsLabel" })</td>
</tr>
i++;
}
</table>
}