var arrPre = new Array(8);
var last_id = 0;

function change(id) {
	if (last_id != id) {
		if (last_id != 0) {
			id1 = 't'+last_id;
			document.getElementById(id1).src = arrPre[last_id+3].src;
		}
		id2 = 't'+id;
		document.getElementById(id2).src = arrPre[id-1].src;
	}
	last_id = id;
}

function preLoad() {
	if(document.images) { 
		var argLen = arguments.length; 
		for(var i = 0; i < argLen; i++) { 
			var arg = arguments[i]; 
			arrPre[i] = new Image();
			arrPre[i].src = "images/"+arg+".gif";
		} 
	}
	arrPre[4] = new Image();arrPre[4].src = "images/t1.gif";
	arrPre[5] = new Image();arrPre[5].src = "images/t2.gif";
	arrPre[6] = new Image();arrPre[6].src = "images/t3.gif";
	arrPre[7] = new Image();arrPre[7].src = "images/t4.gif";
}

function hide(id) {
	id1 = 't'+id;
	document.getElementById(id1).src = arrPre[id+3].src;
}

function out() {
	if (last_id != 0) hide(last_id);
	last_id = 0;
}

function show_div(id,id2) {
	document.getElementById(id).style.display = "inline";	
	document.getElementById(id2).style.display = "none";	
}