function check()
{
	if (apponline.company_cn.value==""){ 
		alert("请填写参展单位名称！");
		apponline.company_cn.focus();		
		return (false);
	}
    if (apponline.company_en.value=="") {
		alert("请填写参展单位名称！");
		apponline.company_en.focus();		
		return (false);
	}
	if (apponline.address_cn.value==""){ 
		alert("请填写参展单位名称地址！");
		apponline.address_cn.focus();		
		return (false);
	}
    if (apponline.address_en.value=="") {
		alert("请填写参展单位名称地址！");
		apponline.address_en.focus();		
		return (false);
	}

   
    if (apponline.tel.value==""&&apponline.mobile.value=="") {
		alert("请填写必要的联系电话！");
		apponline.tel.focus();		
		    return (false);
	}
	if (apponline.email.value=="") {
		alert("请填写E-mail！");
		apponline.email.focus();		
		return (false);
	}
	if (isEmail(apponline.email.value)==false) {
		alert("E-mail格式不对！");
		apponline.email.focus();		
		return (false);
	}
	if (apponline.linkman.value=="") {
		alert("请填写联系人！");
		apponline.linkman.focus();		
		    return (false);
	}
	
	
	if (isNaN(apponline.content_cn.value)){
		alert("请填写具体展出内容！");
		apponline.content_cn.focus();		
		    return (false);
    }
	document.apponline.submit();
}