错误“无法修改标题信息-标题已经发送”。成功提交表单后如何重定向
[英]“Cannot modify header information - headers already sent by” error.How to redirect upon successful submission of the form
问题描述
My code below uses header for redirection upon successful submission of the form and checks if all error variables are set to NULL for redirecting to another php page. 
我下面的代码在成功提交表单时使用标头进行重定向，并检查是否将所有错误变量都设置为NULL以重定向到另一个php页面。 Please help me out as I have tried many ways but none seems to work for conditional redirection. 请尝试帮助我，因为我尝试了很多方法，但似乎没有一种方法可以用于条件重定向。
<?php
$proName=$proNameErr=$email=$emailErr=$catErr='';
if(isset($_POST["submit"]))
{
if (empty($_POST["proName"])) {
$proNameErr = "Product name is required";
}
else if(!preg_match('/^[a-z0-9 .&]+$/i',$_POST['proName'])){
$proNameErr = "Invalid product Name";
}
else{
$proName = test_input($_POST["proName"]);
}
if($_POST['cat']==0)
{
$catErr="please select an option";
}
else
{
$cat=$_POST['cat'];
}
if (empty($_POST["email"])) {
$email = "";
}
else{
$email = test_input($_POST["email"]);
if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
$emailErr = "Invalid email format";
}
}
if($proNameErr=='' && $emailErr=='' && $catErr=='')
{
header("Location: addMedia.php", true, 302);
die();
}
}
function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
<!DOCTYPE html>
<html>
<body>
<h1>ADD Product</h1>
<form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>" method="post" autocomplete="on">
Product Name: <input type="text" name="proName" placeholder="Product Name" maxlength="35" size="40" required value="<?php echo $proName?>">*
<span class="error"><?php echo $proNameErr;?></span><br><br>
Category: <select name="cat" id="cat" size="1" required>
<option value=0>Select...</option>
<option value=1>John</option>
<option value=2>Paul</option>
<option value=3>Ringo</option>
<option value=4>George</option>
<option value=5>ram</option>
<option value=6>rahim</option>
</select>*<span class="error"><?php echo $catErr;?></span><br><br>
Email Address: <input type="email" name="email" value="<?php echo $email?>"> <span class="error"><?php echo $emailErr;?></span><br><br>
<input type="submit" value="submit" name="submit">
</form>
2 个解决方案
解决方案1
0 2015-03-08 15:14:00
Output buffering is your friend in this case. 在这种情况下，输出缓冲是您的朋友。 At the top of each page ( or at the very least, the page in question here ) add 在每个页面的顶部（或至少在这里有问题的页面）添加
ob_start();
/* the rest of the code */
/*and at the end*/
ob_end_flush();
解决方案2
0 已采纳 2015-03-08 15:27:11
You must have outputted something to the browser before header call. 标头调用之前，您必须已向浏览器输出了一些内容。 It cannot be exact copy of your code that you show us. 您向我们展示的代码不能完全相同。 Check: 校验：
is there any html before php opening tag
在php开头标记之前是否有任何html is there any whitespace before php opening tag
php开头标记前是否有空格 is another php script included with echo before that script
是该脚本之前echo中包含的另一个php脚本 is the coding utf8 with BOM?
BOM编码的utf8是什么？
Those are possible reasons of your error. 这些可能是导致您出错的原因。
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