$(document).ready(function(){
    function Slider(activ){
        var direction = $(':checkbox');
        
        this.activation = function(){
            activ.click(function(){
              if($(this).attr('checked'))
                SelectAll();
              else
                disabledAll();
            })
        }
        
        function disabledAll(){
            direction.each(function(){
                $(this).removeAttr('checked');
            });
        }
        
        function SelectAll(){
            direction.each(function(){
                $(this).attr('checked', 'checked');
            });
        }
    var act = new Slider($('#activate_checkboxes'));
    act.activation();
    }
})

<input type="checkbox" id="activate_checkboxes" name="check" />
<hr />
<form action="" method="post">
<input type="checkbox" name="check1" value="1" />
<input type="checkbox" name="check2" value="2" />
<input type="checkbox" name="check3" value="3" />
<input type="checkbox" name="check4" value="4" />
<input type="checkbox" name="check5" value="5" />
<input type="checkbox" name="check6" value="6" />
</form>

$(document).ready(function(){
    $('#activate_checkboxes').click(function(){
        if($(this).attr('checked')){
            $("input:checkbox").attr('checked', 'checked');
        } else {
            $("input:checkbox").removeAttr('checked');
        }
    });    
});