function switchCategory(e){
	var ee=$(e.parentNode.parentNode).childElements()[1];
	if($(ee).getStyle('display')=='none'){
		ee.setStyle({display:''});
		e.childNodes[0].src='/zh/style/images/unfolded.gif';
	}else{
		ee.setStyle({display:'none'});
		e.childNodes[0].src='/zh/style/images/folded.gif';
	}
}