Javascript: Check all checkboxes (button)

gistfile1

$('#checkIt').click(function() {
                        if(this.value === 'notChecked'){
                            $('#educationCheckbox :checkbox').each(function() {
                            this.checked = true;  });
                            $('#checkIt').val('checked').html('Fjern alle');
                          }
                          else{
                            $('#educationCheckbox :checkbox').each(function() {
                            this.checked = false;  });
                            $('#checkIt').val("notChecked").html('Vælg alle');
                          }
                });