Set JQuery HTML javascript Checkbox working but not showing as checked

Set JQuery HTML javascript Checkbox working but not showing as checked

All im trying to do is check if a checkbox is checked, if so, uncheck it.
The checkbox is being set properly but not showing as checked. I have
check this my putting a checkbox outside the <li> and it works fine
Here is my current HTML:
<input onclick="selectAll()" type="button" id="checkAll" value="Check All" />
<li>
<a href="#" style="padding-top: 0px; padding-bottom: 0px;
padding-right: 0px; padding-left: 0px;">
<label style="border-top-width: 0px; margin-top: 0px;
border-bottom-width: 0px; margin-bottom: 0px;
border-left-width: 0px; border-right-width: 0px;"
data-corners="false">
<fieldset data-role="controlgroup">
<input type="checkbox" name="checkboxProd"
id="checkboxProd2" data-theme="c"
checked="checked" />
<label for="checkboxProd2"
style="border-top-width: 0px; margin-top: 0px;
border-bottom-width: 0px; margin-bottom: 0px;
border-left-width: 0px; border-right-width:
0px;">
<h3>Black Denim</h3>
</label>
<table id="OrderDetailsTable2" border="0"
style="background-color: transparent;
border-color: transparent; color: transparent;
width: 250px; font-size: small; padding: 0;
padding-left: 3em;">
</table>
</fieldset>
</label>
</a>
</li>
and my Javascript/Jquery:
function selectAll()
{
if ($('#checkboxProd2').prop('checked'))
{
alert("checked");
$('#checkboxProd2').prop('checked', false);
}
}