Check and Uncheck Checkbox Dynamically with jQuery : bug?

Question

I made a script in order to control master & slave checkboxes (automatic checking and unchecking).

Here is my JS :

$(document).ready(function() {

    $('#myCheck').click(function() {
        $('.myCheck').attr('checked', false);
    });
    $('.myCheck').click(function() {
        if ($('.myCheck').is(':checked')) {
            $('#myCheck').attr('checked', false);
        } else {
            $('#myCheck').attr('checked', true); // IT DOESN'T WORK, WHY ?
            alert("Checkbox Master must be checked, but it's not!");
        }
    });

});

And here is my HTML :

<input type="checkbox" id="myCheck" checked="checked" />&nbsp;&nbsp;Checkbox Master<br />
<input type="checkbox" class="myCheck" value="1" />&nbsp;&nbsp;Checkbox Slave 1<br />
<input type="checkbox" class="myCheck" value="1" />&nbsp;&nbsp;Checkbox Slave 2

Look at my simple JsFiddle to understand the problem.

EDIT 1 : Like Inser said, the problem happens with jQuery 1.9.2 and over. No more problem with jQuery 1.8.3. Strange...

EDIT 2 : Inser found the solution, use .prop('checked', true) instead .attr('checked', true). Look at the comments below...

Answer 1

Use prop method for new versions of jQuery:

$('#myCheck').prop('checked', true);
$('#myCheck').prop('checked', false);

http://jsfiddle.net/uQfMs/37/

Answer 2

You could try this.

$('#myCheck').click(function() {
    var checkBoxes = $(this).siblings('input[type=checkbox]');
    checkBoxes.prop('checked', $(this).is(':checked') ? true : false);
});