function  mouse(){
 if(document.myfrom.mybox6.checked==true)
     {
       var a5 = window.document.getElementById("mouse_a5").value;
       var total = 5 * a5;
       window.document.getElementById("mouse_total").value = total;
    }
  else
      {
       window.document.getElementById("mouse_num").disabled=true;
       window.document.getElementById("mouse_total").value = 1.25;
 }
}