if (document.images)
   {
     image01= new Image(100,100);
     image01.src="/media/images/matching/chimp01.jpg";  
     image02= new Image(100,100);
     image02.src="/media/images/matching/chimp02.jpg";
	 image03= new Image(100,100);
     image03.src="/media/images/matching/chimp03.jpg";
	 image04= new Image(100,100);
     image04.src="/media/images/matching/chimp04.jpg"; 
	 image05= new Image(100,100);
     image05.src="/media/images/matching/chimp05.jpg"; 
	 image06= new Image(100,100);
     image06.src="/media/images/matching/chimp06.jpg"; 
	 image07= new Image(100,100);
     image07.src="/media/images/matching/banana.jpg"; 
   }
   
var gamenotstarted = true;

function startgame() {
 pics = new Array("/media/images/matching/chimp01.jpg","/media/images/matching/chimp02.jpg","/media/images/matching/chimp03.jpg","/media/images/matching/chimp04.jpg","/media/images/matching/chimp05.jpg","/media/images/matching/chimp06.jpg");
   picused = new Array(0,0,0,0,0,0,2);
   placement = new Array(13);             // this array tracks the hidden images
   blankcard = false;
   gamenotstarted = false;
   for (var img=1; img < 13; img++) {     // for each image in the Image array
      index = 6;                          // dummy value for while loop
      while (picused[index] == 2) {index = Math.floor(Math.random() * pics.length)}
      picused[index]++;
      document.images[img].src="/media/images/matching/banana.jpg";   // display the blank image
      placement[img] = index;                 // note which image is hidden
      }
   //  set all initial values
   matches = 0;
   tries = 0;
   firstcard = true;
   oldcard = 0;
   firstimg = 1;
   document.game.numtry.value = "";
   document.game.message.value = "";
   blankup = new Array(14);            // is blank card showing?
   for (var blnk=0; blnk < 14; blnk++) {blankup[blnk] = true}
   }   // end function startgame

function showcard(imgnum) {
   document.game.message.value = " ";
   if (gamenotstarted) {StartGame()}
   if (blankup[imgnum]) {
      document.images[imgnum].src = pics[placement[imgnum]];
      if (firstcard) {                   // first of two clicks?
         if (blankcard) {                // do we blank previous cards?
            document.images[tempimg].src = "../media/images/matching/banana.jpg";
            document.images[tempfirst].src = "../media/images/matching/banana.jpg";
            document.images[imgnum].src = pics[placement[imgnum]];
            blankcard = false;
            }
         oldcard = placement[imgnum];
         firstimg = imgnum;
         firstcard = false;
         tries++;
         document.game.numtry.value = tries;
         }
      else {                             // second of two clicks
         if (imgnum == firstimg)         // clicked the same card?
            {document.game.message.value = 'Click a different card.'}
         else {
            if (placement[imgnum] == oldcard) {      // is it a match?
               matches++;
               if (matches < 6) {
                  MsgText = "They match!";
                  blankcard = false;
                  }
               else {
                  MsgText = "Great job! You won!";
                  gamenotstarted = true;
                  }
               document.game.message.value = MsgText;
               blankup[imgnum] = false;
               blankup[firstimg] = false;
               }
            else {                       // not a match
               MsgText = "Sorry, no match.";
               document.game.message.value = MsgText;
               blankcard = true;
               tempimg = imgnum;
               tempfirst = firstimg;
               }
            firstcard = true;
            firstimg = 1;
            }
         }
      }
   else { window.alert("You must select a blank card.", imgnum) }
   }   // end function showcard