你需要把你所有的 php 代码放在里面if (isset($_POST["submit"]))，因为!isset当你load的 php 页面时条件总是为真。在您的代码中进行以下更改：
if (isset($_POST["submit"])) {
$errName ="";
$errEmail ="";
$errMessage ="";
$result="";
$name = $_POST['name'];
$business = $_POST['business'];
$email = $_POST['email'];
$message = $_POST['message'];
$from = '------';
$to = '-----';
$subject = 'Message from user on website';
$body ="-------";
// Check if name has been entered
if (!isset($_POST) || !key_exists('name', $_POST) || !filter_var($_POST['name'])) {
$errName = 'Please enter your name';
}
// Check if email has been entered and is valid
if (!isset($_POST) || !key_exists('email', $_POST) || !filter_var($_POST['email'], FILTER_VALIDATE_EMAIL)) {
$errEmail = 'Please enter a valid email address';
}
//Check if message has been entered
if (!isset($_POST) || !key_exists('message', $_POST) || !filter_var($_POST['message'])) {
$errMessage = 'Please enter your message';
}
// If there are no errors, send the email
if (!isset($errName) && !isset($errEmail) && !isset($errMessage)) {
$result .= '<br><div class="alert alert-success">Thank You! We will be in touch</div>';
} else {
$result .= '<br><div class="alert alert-danger">Sorry there was an error sending your message. Please try again later.</div>';
}
} // end of isset
MYYA