var isDOM = (document.getElementById ? true : false); 
var isIE4 = ((document.all && !isDOM) ? true : false);
var isNS4 = (document.layers ? true : false);
var isNS = navigator.appName == "Netscape";

function getRef(id) {
	if (isDOM) return document.getElementById(id);
	if (isIE4) return document.all[id];
	if (isNS4) return document.layers[id];
}

function getSty(id) {
	x = getRef(id);
	return (isNS4 ? getRef(id) : getRef(id).style);
}

var rollFlag=0;
        
function roll_up(img_num) 
{
//    document.images["roll" + img_num].src = "img/service/roll_up.gif";
}

function roll_down(img_num) 
{
//    document.images["roll" + img_num].src = "img/service/roll_down.gif";
}

function txt_roll(str)
{
    sub_num = str.substring(str.length - 2);
    sub_str = str.substring(0, str.length -2);

    if (document.all[str].style.display=="")
    {
        document.all[str].style.display="none";
        roll_up(sub_num);
        rollFlag=0;
        return;
    }
    else
        {
        if(rollFlag != 0)
        {
            document.all[sub_str+rollFlag].style.display="none";
            roll_up(rollFlag);
            document.all[str].style.display="";
            roll_down(sub_num);
        }
    
        document.all[str].style.display="";
        roll_down(sub_num);
        rollFlag=sub_num;
    }
    
}