//diable shift key

   e.ShiftKey = false;

//Enable shift key with ARROW key left(37) and right(39)
    if (e.shiftKey) {

     if(e.keyCode == 37 || e.keyCode == 39)
     {
        return true;
        }

    }
//Enable Ctrl key with A (Ctrl+A) 
    if (isCtrl == true && e.which == '65') { return true; }
(for chrome)
    if (e.ctrlKey == true && e.keyCode == '65') { return true; }

Enable and disable shift and ctrl key with some of there comibinations

JavaScript