Jquery "select all" checkbox

Question

I am trying to select all checkboxes on a page once the 'select all' checkbox is clicked and i am using jquery for this as you can see at the below link:

http://jsfiddle.net/priyam/K9P8A/

The code to select and unselect all checkbox is:

function selectAll() {
    $('.selectedId').attr('checked', isChecked('selectall'));
}

function isChecked(checkboxId) {
    var id = '#' + checkboxId;
    return $(id).is(":checked");
}

After being stuck with it for a day, I am still not sure why I cant get it to work. Please help

Answer 1

Why don't you do it this way? It is more clear and readable

$('#selectall').click(function () {
    $('.selectedId').prop('checked', this.checked);
});

$('.selectedId').change(function () {
    var check = ($('.selectedId').filter(":checked").length == $('.selectedId').length);
    $('#selectall').prop("checked", check);
});

DEMO