function check() {

	if (document.index_ly.contact.value==""){
		alert ("您好,联系人不能为空！");	
		document.index_ly.contact.focus();
		return false;
	}
		if (document.index_ly.liuyu_content.value == ""){
		alert ("您好,留言内容不能为空！");	
		document.index_ly.liuyu_content.focus();
		return false;
	}
		if (document.index_ly.email.value==""){
		alert ("email不能为空！");	
		document.index_ly.email.focus();
		return false;
	}
			if (document.index_ly.phone.value==""){
		alert ("手机/电话不能为空！");	
		document.index_ly.phone.focus();
		return false;
	}
	return true;
}