var selected_left_ID = "";
	var selected_top_ID = "";
	var selected_middle_ID = "";

	function set_Button(img,sort){
		name = img.src;
		name = name.substring(0, name.lastIndexOf("_")+1)+"down.gif";
		img.src = name;
		if(sort == "top"){
			selected_top_ID = img.id;
		}else if(sort == "left"){
			selected_left_ID = img.id;
		}else if(sort == "middle"){
			selected_middle_ID = img.id;
		}
	}

	function upImage(img){
		if(img.id != selected_top_ID && img.id != selected_left_ID && img.id != selected_middle_ID){
			name = img.src;
			
			name = name.substring(0, name.lastIndexOf("_")+1)+"up.gif";
			img.src = name;
		}
	}
	
	function downImage(img){
		if(img.id != selected_top_ID && img.id != selected_left_ID && img.id != selected_middle_ID){
			name = img.src;
			
			name = name.substring(0, name.lastIndexOf("_")+1)+"down.gif";
			img.src = name;
		}
	}