var circle = new Image();
circle.src = "mem_cir.gif";
var logo = new Image();
logo.src = "mem_logo.gif";
var square = new Image();
square.src = "mem_square.gif";
var tri = new Image();
tri.src = "mem_tri.gif";
var img16 = new Array(16);
var codes = new Array(16);
var tijd;

function play(){
 var cells = new Array(16);	
	if(tijd != undefined)
	 clearInterval(tijd);
	
	if(document.getElementById)
	 for(i=1;i<17;i++)
		 cells[i] = document.getElementById("cell" + i);
	else if(document.all)
	 for(i=1;i<17;i++)
		 cells[i] = document.all["cell" + i];
	else if(document.layers)
	 for(i=1;i<17;i++)
		 cells[i] = document.layers["cell" + i];
	
	for(i=1;i<17;i++)
  cells[i].innerHTML = "<img name=\"i" + i + "\" src=\"mem_logo.gif\" width=\"40\" height=\"40\">";

 var source = new Array(circle,circle,circle,circle,logo,logo,logo,logo,square,square,square,square,tri,tri,tri,tri);

	for(i=1;i<17;i++)
		img16[i] = source.splice(Math.floor(Math.random()*source.length),1)[0];
	
	for(i=1;i<17;i++){
	 var img = eval("document.images.i" + i);
		img.src = img16[i].src;
	}
	tijd = setInterval("play2()",16000);
}

function play2(){
 var source = new Array(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16);
	var cells = new Array(16);	
	clearInterval(tijd);	
	for(i=1;i<17;i++)
		codes[i] = source.splice(Math.floor(Math.random()*source.length),1)[0];	
	if(document.getElementById)
	 for(i=1;i<17;i++)
		 cells[i] = document.getElementById("cell" + i);
	else if(document.all)
	 for(i=1;i<17;i++)
		 cells[i] = document.all["cell" + i];
	else if(document.layers)
	 for(i=1;i<17;i++)
		 cells[i] = document.layers["cell" + i];
	
	for(i=1;i<17;i++)
  cells[i].innerHTML = codes[i];

	for(i=0;i<document.forms.mem.logo.length;i++)
	 document.forms.mem.logo[i].value = "";
	for(i=0;i<document.forms.mem.circle.length;i++)
	 document.forms.mem.circle[i].value = "";
	for(i=0;i<document.forms.mem.square.length;i++)
	 document.forms.mem.square[i].value = "";
	for(i=0;i<document.forms.mem.tri.length;i++)
	 document.forms.mem.tri[i].value = "";
}

function score(){
 var result = 0;
	var guess;
	if(document.forms.mem.logo[0].value != ""){
	 guess = parseInt(document.forms.mem.logo[0].value);
		if(img16[arrayPos(codes,guess)] == logo)
			 result++;
		else
			 result--;
	}	
	if(document.forms.mem.logo[1].value != ""){
	 guess = parseInt(document.forms.mem.logo[1].value);
		if(img16[arrayPos(codes,guess)] == logo)
			 result++;
		else
			 result--;
	}	
	if(document.forms.mem.logo[2].value != ""){
	 guess = parseInt(document.forms.mem.logo[2].value);
		if(img16[arrayPos(codes,guess)] == logo)
			 result++;
		else
			 result--;
	}	
	if(document.forms.mem.logo[3].value != ""){
	 guess = parseInt(document.forms.mem.logo[3].value);
		if(img16[arrayPos(codes,guess)] == logo)
			 result++;
		else
			 result--;
	}
	if(document.forms.mem.circle[0].value != ""){
	 guess = parseInt(document.forms.mem.circle[0].value);
		if(img16[arrayPos(codes,guess)] == circle)
			 result++;
		else
			 result--;
	}	
	if(document.forms.mem.circle[1].value != ""){
	 guess = parseInt(document.forms.mem.circle[1].value);
		if(img16[arrayPos(codes,guess)] == circle)
			 result++;
		else
			 result--;
	}	
	if(document.forms.mem.circle[2].value != ""){
	 guess = parseInt(document.forms.mem.circle[2].value);
		if(img16[arrayPos(codes,guess)] == circle)
			 result++;
		else
			 result--;
	}	
	if(document.forms.mem.circle[3].value != ""){
	 guess = parseInt(document.forms.mem.circle[3].value);
		if(img16[arrayPos(codes,guess)] == circle)
			 result++;
		else
			 result--;
	}	
	if(document.forms.mem.square[0].value != ""){
	 guess = parseInt(document.forms.mem.square[0].value);
		if(img16[arrayPos(codes,guess)] == square)
			 result++;
		else
			 result--;
	}	
	if(document.forms.mem.square[1].value != ""){
	 guess = parseInt(document.forms.mem.square[1].value);
		if(img16[arrayPos(codes,guess)] == square)
			 result++;
		else
			 result--;
	}
	
	if(document.forms.mem.square[2].value != ""){
	 guess = parseInt(document.forms.mem.square[2].value);
		if(img16[arrayPos(codes,guess)] == square)
			 result++;
		else
			 result--;
	}	
	if(document.forms.mem.square[3].value != ""){
	 guess = parseInt(document.forms.mem.square[3].value);
		if(img16[arrayPos(codes,guess)] == square)
			 result++;
		else
			 result--;
	}	
	if(document.forms.mem.tri[0].value != ""){
	 guess = parseInt(document.forms.mem.tri[0].value);
		if(img16[arrayPos(codes,guess)] == tri)
			 result++;
		else
			 result--;
	}	
	if(document.forms.mem.tri[1].value != ""){
	 guess = parseInt(document.forms.mem.tri[1].value);
		if(img16[arrayPos(codes,guess)] == tri)
			 result++;
		else
			 result--;
	}	
	if(document.forms.mem.tri[2].value != ""){
	 guess = parseInt(document.forms.mem.tri[2].value);
		if(img16[arrayPos(codes,guess)] == tri)
			 result++;
		else
			 result--;
	}	
	if(document.forms.mem.tri[3].value != ""){
	 guess = parseInt(document.forms.mem.tri[3].value);
		if(img16[arrayPos(codes,guess)] == tri)
			 result++;
		else
			 result--;
	}
	document.forms.mem.results.value = result;

	for(i=0;i<document.forms.mem.logo.length;i++)
	 document.forms.mem.logo[i].value = "";
	for(i=0;i<document.forms.mem.circle.length;i++)
	 document.forms.mem.circle[i].value = "";
	for(i=0;i<document.forms.mem.square.length;i++)
	 document.forms.mem.square[i].value = "";
	for(i=0;i<document.forms.mem.tri.length;i++)
	 document.forms.mem.tri[i].value = "";
}

function arrayPos(arr,n){
 for(i=0;i<arr.length;i++)
	 if(arr[i] == n)
		 return i;
}