function check_form()
{
	if(document.getElementById("user_name").value==""){
		alert("Input fullname!");
		document.getElementById("user_name").focus();
		return false;
	}
		if(document.getElementById("ly_content").value==""){
		alert("Input Comments!");
		document.getElementById("ly_content").focus();
		return false;
	}
		if(document.getElementById("check_code").value==""){
		alert("Input check code!");
		document.getElementById("check_code").focus();
		return false;
	}

  
  if(document.getElementById("user_email").value!="")
  {
	  var s=document.getElementById("user_email").value;
	  var reg=/^[_\.0-9a-zA-Z-]+@([0-9a-zA-Z][0-9a-zA-Z-]+\.)+[a-zA-Z]{2,3}$/;
	  if(!reg.test(s))
	  {
	     alert("Email error!");
	     return false;
	  }
  }

}