// JavaScript Document
function byID(_id){
var el;
if(document.getElementById){ return document.getElementById(_id); }
if(document.all){ return document.all(_id); }
}

function OC(num){
if(byID('cont'+num) && byID('menu_img'+num)){
var li = byID('cont'+num).style;

if(li.display != 'block'){ //開く
li.display = 'block';
byID('menu_img'+num).src = 'images/folder/lmh.gif';

}else{ //閉じる
li.display = 'none';
byID('menu_img'+num).src = 'images/folder/lph.gif';

}
}
}