为什么javascript的报错没什么用
要崩溃了，为什么javascript的报错没什么用？
<?php

include("conn.php");

if(isset($_POST["submit"]))
{
$sql="INSERT INTO message (id,user,title,content,lastdate) " .
  "values ('','$_POST[user]','$_POST[title]','$_POST[content]',now())";
  //echo $sql;
  $result = mysql_query($sql,$conn)or die(mysql_error());
}


?>

  <SCRIPT language=javascript>
function CheckPost()
{
  if (myform.user.value=="")
  {
  alert("please enter the name");
  myform.user.focus();
  return false;
}
}

  </SCRIPT>

  <form action="submit.php" method="post" name="myform" onsubmit="return CheckPost();">

  user:<input type="text" name="user" value="" size="10" maxlength="40"/><br>
  title:<input type="text" name="title"/><br>
  content:<textarea name="content" rows="10" cols="50" ></textarea><br>

  <input type="submit" name="submit" value="click"/>

  </form>


------解决方案--------------------
if (document.myform.user.value=="")