Selects all checkboxes in a asp.net gridview

Check All Checkboxes.js

var gridView = '#<%= gridViewId.ClientID%>';
var checkAll = '#checkBoxId';

$(checkAll).click(function (i, v) {
    $('input[type=checkbox]', gridView).prop('checked', this.checked);
});

var checkCount = $('input[type=checkbox]', gridView).length;
$('input[type=checkbox]', gridView).click(function (i, v) {
    $(checkAll).prop('checked', $('input:checked', gridView).length == checkCount);
});

Revised the original one, this will select and deselect all checkboxes. If one of the gridview checkboxes is unchecked the select all will deselect itself.