function placehoder(){
	var keys = Jtrim(document.searchform.keys.value);
	if(keys.length<1){
		window.alert ("请输入搜索关键词！");
		document.searchform.keys.focus();
		return false;
	}	
	if(keys.indexOf('输入关键')>=0 || keys.indexOf('输入搜索')>=0){
		window.alert ("请输入搜索关键词！");
		document.searchform.keys.value = '';
		document.searchform.keys.focus();
		return false;
	}	
	document.searchform.action="http://www.21food.cn/placehoder.jsp";	
	return true;
}