JQuery :: Cannot Count Number Of Checked Items

Using Microsoft built-in jquery files, when counting numbers of checked checkbox, the jquery-1.4.2.min.js cannot count the correct result ,however, the version jquery-1.3.2.min.js gives out the correct one, why?

$("#check").click(function () {
var nameSports = new Array();
var i = 0;
$('input[name=selector]:checked').each(function () {
nameSports[i] = jQuery(this).val();
i += 1;
});
if (loopCounter != 0) {
alert(i);
}
});
<input type="checkbox" value="1" name="selector">
<input type="checkbox" value="2" name="selector">
<input type="checkbox" value="3" name="selector">
<a id="check">Check Items</a>