var num = 0;

Image1on = new Image();                
Image1on.src = "http://www.myusvisa.com/img/0408/mid6/m6_menu1_1.gif"; // ¸¶¿ì½º¸¦ ¿Ã·ÈÀ»¶§ÀÇ À̹ÌÁö
Image1off = new Image();
Image1off.src = "http://www.myusvisa.com/img/0408/mid6/m6_menu1.gif"; // Æò»ó½ÃÀÇ À̹ÌÁö

Image2on = new Image();                
Image2on.src = "http://www.myusvisa.com/img/0408/mid6/m6_menu2_1.gif";
Image2off = new Image();
Image2off.src = "http://www.myusvisa.com/img/0408/mid6/m6_menu2.gif";

Image3on = new Image();                
Image3on.src = "http://www.myusvisa.com/img/0408/mid6/m6_menu3_1.gif";
Image3off = new Image();
Image3off.src = "http://www.myusvisa.com/img/0408/mid6/m6_menu3.gif";

Image4on = new Image();                
Image4on.src = "http://www.myusvisa.com/img/0408/mid6/m6_menu4_1.gif";
Image4off = new Image();
Image4off.src = "http://www.myusvisa.com/img/0408/mid6/m6_menu4.gif";


function img_act(imgname) {
	imgOn = eval(imgname + "on.src");
				document [imgname].src = imgOn;
}
function img_inact(imgname) {
	imgOff = eval(imgname + "off.src");
	document [imgname].src = imgOff;
}
function inact(imgname) {
	img_inact(imgname);
	change(0);
}
function change(selected_num) {
	if(selected_num != 0) {
		num = selected_num;
	}
	for(i = 1; i <= 4; i++) {
		imgname = "Image" + i;

		if(num !=i ) {
			img_inact(imgname);
		} else {
			img_act(imgname);
		}
	}
}