我已经注意到关于这个主题的很多问题，但是，他们都提到<div>声明没有准备好。我的是。在单击按钮之前，不会调用document.getElementById（）函数。
困扰我的是，我有3个document.getElementById（）调用，它是中间问题。
我的页面....
<?php
(reference to session etc here)
$user = (array_key_exists('LoggedInUser', $_SESSION)) ? $_SESSION['LoggedInUser'] : '';
$HeaderLinks = "<A onclick='javascript:LoadPage(\"Admin\");' href='javascript:void(0);'>Home</A> | <A onclick='javascript:LoadPage(\"LogOut\");' href='javascript:void(0);'>Log out</A>"; // home and logout links
$LoggedInUser = ($user == '') ? ' ': "Logged in as: <B>$user</B>";
$HeaderLinks = ($user == '') ? ' ': $HeaderLinks;
?>
<BODY>
<div class='main_disply_space center'> <!-- MAIN DISPLAY SPACE -->
<!-- HEADER SECTION START -->
<div class='page_header'> <!-- HEADER -->
<div class='title container'>
blah blah
<div class='subtitle contained'>
blah blah
</div>
</div>
</div> <!-- HEADER end -->
<div class='userandlinks'> <!-- USER and LINKS -->
<div class='user container' id='LoggedInUser'>
<?php echo $LoggedInUser; ?>
<div class='links contained' id='AdminLinks'>
<?php echo $HeaderLinks; ?>
</div>
</div>
</div> <!-- USER and LINKS end -->
<!-- HEADER SECTION END -->
<!-- BODY SECTION START -->
<div class=body id='ActivePage'> <!-- DISPLAY AREA -->
</div> <!-- DISPLAY AREA end -->
<!-- BODY SECTION END -->
<!-- FOOTER SECTION START -->
<div class='footerlinks' id='FooterLinks'> <!-- LINKS -->
<?php echo $HeaderLinks; ?>
</div> <!-- LINKS end -->
<div class='copyright'> <!-- COPYRIGHT -->
more blah blah
</div> <!-- COPYRIGHT end -->
<!-- FOOTER SECTION END -->
</div> <!-- MAIN DISPLAY SPACE end -->
</BODY>
javascript ...
send = "username=" + user + "&password=" + pwd;
if(btn === 'Add')
{
if(RunPHPFile('AdminUserAdd', send) === '1')
if(RunPHPFile('UserLogin', send) === '1')
{
// Show who's logged in
document.getElementById("LoggedInUser").innerHTML = 'Logged in as: <B>'+user+'</B>';
// show home and logout links
HLinks = "<A onclick='javascript:LoadPage(\"Admin\");' href='javascript:void(0);'>Home</A> | <A onclick='javascript:LoadPage(\"LogOut\");' href='javascript:void(0);'>Log out</A>";
document.getElementById('AdminLinks').innerHTML = HLinks;
document.getElementById('FooterLinks').innerHTML = HLinks;
LoadPage('Admin');
}
else
document.getElementById('error').innerHTML = 'Error logging in new user.';
else
document.getElementById('error').innerHTML = 'Error adding new user.';
}
我在document.getElementById（）上使用了几个try {} catch（）{}来查找它无法正常工作的原因。
继承人的困惑。在javascript中，你可以看到3个document.getElementById（）的一个接一个，'LoggedInUser'，'AdminLinks'和＆amp; 'FooterLinks'。在HTML中，您可以看到相应的id =''。 现在，我的问题是'LoggedInUser'和'FooterLinks'都可以正常工作，但'AdminLinks'会引发'is null'错误。我一遍又一遍地编码，我看不出问题所在。
答案 0 :(得分：3)
您正在替换SELECT H.vehicle_code,
G.group_name,
cast(Count(DISTINCT D.cusip_sedol) as DECIMAL)/cast(count(DISTINCT G.group_name) as DECIMAL) AS Total --add this second part
FROM tbltrading_holdings AS H
INNER JOIN tbltrading_stocks_data_stocks AS D
ON H.cusip_sedol = D.cusip_sedol
LEFT JOIN tbltrading_gic AS G
ON D.gic_code = G.gic_code
WHERE vehicle_code IN (SELECT vehicle_code
FROM tbltrading_vehicles
WHERE vehicle_name LIKE 'J%')
AND D.gic_code IS NOT NULL
GROUP BY H.vehicle_code,
G.group_name
ORDER BY vehicle_code
的内容。猜猜#LoggedInUser div中有什么？那是对的 - #LoggedInUser。所以#AdminLinks返回null，因为 - 页面上没有带有该id的元素。