var img1 = new Image();
var img2 = new Image();
img1.src = "Images/i_plus.gif";
img2.src = "Images/i_minus.gif";

function doOutline() {
  	var srcId, srcElement, targetElement;
  	srcElement = window.event.srcElement;
	if (srcElement.className.toUpperCase() == "LEVEL1") {
		srcID = srcElement.id.substr(0, srcElement.id.length-1);
		targetElement = document.all(srcID + "s");
		srcElement = document.all(srcID + "i");
	  	if (targetElement.style.display == "none") {
			targetElement.style.display = "";
 		 	if (srcElement.className == "Level1") srcElement.src = img2.src;
   		} else {
			targetElement.style.display = "none";
		 	if (srcElement.className == "Level1") srcElement.src = img1.src;
    	}
  	}

  if (srcElement.className.toUpperCase() == "LEVEL2") {
		 srcID = srcElement.id.substr(0, srcElement.id.length-2);
		 targetElement = document.all(srcID + "ss");
		 srcElement = document.all(srcID + "ii");
  	if (targetElement.style.display == "none") {
				 targetElement.style.display = "";
		 		 if (srcElement.className == "Level2") srcElement.src = img2.src;
     	} else {
				 targetElement.style.display = "none";
				 if (srcElement.className == "Level2") srcElement.src = img1.src;
     }
  }

	if (srcElement.className.toUpperCase() == "LEVEL3") {
		srcID = srcElement.id.substr(0, srcElement.id.length-2);
		targetElement = document.all(srcID + "sg");
		srcElement = document.all(srcID + "ig");
	  	if (targetElement.style.display == "none") {
			targetElement.style.display = "";
			srcElement.src = img2.src;
   		} else {
			targetElement.style.display = "none";
			srcElement.src = img1.src;
    	}
  	}

  	if (srcElement.className.toUpperCase() == "LEVEL4") {
		srcID = srcElement.id.substr(0, srcElement.id.length-3);
		targetElement = document.all(srcID + "ssg");
		srcElement = document.all(srcID + "iig");
  		if (targetElement.style.display == "none") {
			targetElement.style.display = "";
			srcElement.src = img2.src;
     	} else {
			targetElement.style.display = "none";
			srcElement.src = img1.src;
     	}
  	}
}

document.onclick = doOutline;