if(document.images){
     button1 = new Image;
     button12 = new Image;
     button2 = new Image;
     button22 = new Image;
     button3 = new Image;
     button32 = new Image;
     button4 = new Image;
     button42 = new Image;
     button5 = new Image;
     button52 = new Image;
     button6 = new Image;
     button62 = new Image;
    
      button1.src = "../images/casem.gif";
      button12.src = "../images/casemon.gif";
      button2.src = "../images/tech.gif";
      button22.src = "../images/techon.gif";
      button3.src = "../images/revsyst.gif";
      button32.src = "../images/revsyston.gif";
      button4.src = "../images/revserv.gif";
      button42.src = "../images/revservon.gif";
      button5.src = "../images/staff.gif";
      button52.src = "../images/staffon.gif";
      button6.src = "../images/costore.gif";
      button62.src = "../images/costoreon.gif";

  }
  else{
        button1 = "";
        button12 = "";
								document.casebutton = "";

        button2 = "";
        button22 = "";
								document.techplusbutton = "";

        button3 = "";
        button32 = "";
								document.revsystplusbutton = "";

        button4 = "";
        button42 = "";
								document.revservplusbutton = "";

        button5 = "";
        button52 = "";
								document.staffplusbutton = "";

        button6 = "";
        button62 = "";
								document.costorebutton = "";
 }