// ******************************************************************
  // Titel   : Tetris Read Event Key from Keyboard
  // Autor   : Informatik Atelier Bern / Dimitri Jeanneret 
  // Datum   : Januar 09
  // Version : 1.0
  // ******************************************************************   
  var KeyEvent_Ready = true;
  // ---------------------------------------------- 
  // Keyboard  Key Event 
  document.onkeydown = function (evnt) 
  {
    
    if (ActiveForm == -1 || !KeyEvent_Ready) return;
    
    KeyEvent_Ready = false; // Lock function
    
    var keycode = 0;
    
    if (!evnt)
      evnt = window.event;
    if (evnt.which) {
      keycode = evnt.which;
    } else if (evnt.keyCode) {
      keycode =  evnt.keyCode;
    } 
    
    // Left Form
    if (keycode == 37 && Check_LeftPos()) // ARROW LEFT
    {
      Form_Grid_Loeschen(); 
      ActivePosX--;
      Grid_Aktualisieren(); 
    } 
    
    // Right Form       
    if (keycode == 39 && Check_RightPos()) // ARROW RIGHT
    {
      Form_Grid_Loeschen(); 
      ActivePosX++;
      Grid_Aktualisieren();
    }
    
    
    // Turn Form right
    if (keycode == 38) // ARROW HIGH
    {
      Form_Grid_Loeschen();
      if (Check_Turn('right'))
      {
        ActiveOrientierung++;
        if (ActiveOrientierung < 0 || ActiveOrientierung >3) ActiveOrientierung=0;
      }
      Grid_Aktualisieren();
    }
 
    // Turn Form left
    if (keycode == 40 && false) // ARROW LOW
    {
      Form_Grid_Loeschen();
      if (Check_Turn('left'))
      {
        ActiveOrientierung--;
        if (ActiveOrientierung < 0 || ActiveOrientierung >3) ActiveOrientierung=3;
      }
      Grid_Aktualisieren();
    }
    
    // Low Form 
    if ((keycode == 40 || keycode == 32) && !Wait_FormFix && !Wait) // ARROW LOW (40) or SPACE (32)
    {
      Score++;
      Form_Down();
    }
    
    KeyEvent_Ready = true; // Relaese Lock function
    
  }
  // ----------------------------------------------