Jquery “select all” checkbox

[Ozxagitl]

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:\[code\]function selectAll() { $('.selectedId').attr('checked', isChecked('selectall'));}function isChecked(checkboxId) { var id = '#' + checkboxId; return $(id).is(":checked");}\[/code\]After being stuck with it for a day, I am still not sure why I cant get it to work. Please help