由于某种原因，来自我的 PHP 的 ajax.responseTest 将无法在下面的 javascript 条件代码中正确评估。ajax.responseTest 以“signup_success”的形式返回（我用警告框检查了它，它肯定会正确返回），但我的 JS 代码中的条件不会正确评估。
这是javascript：
else {
_("signupbtn").style.display = "none";
status.innerHTML = 'please wait ...';
var ajax = ajaxObj("POST", "signup.php");
ajax.onreadystatechange = function() {
if(ajaxReturn(ajax) == true) {
if(ajax.responseText != "signup_success"){
status.innerHTML = ajax.responseText;
_("signupbtn").style.display = "block";
} else {
_("sign").innerHTML = ajax.responseText;
window.scrollTo(0,0);
_("signupform").innerHTML = "OK "+u+", check your email inbox and junk mail box at <strong>"+e+"</strong> in a moment to complete the sign up process by activating your account. You will not be able to do anything on the site until you successfully activate your account.";
}
}
}
ajax.send("u="+u+"&e="+e+"&p="+p1+"&g="+g);
}
如果我将 "ajax.responseText != "signup_success" " 中的逻辑运算符更改为 "==" ，则 else 块将运行，因此在条件逻辑之前没有其他问题，并且我已经对其和 PHP 进行了测试（如下) 肯定会返回“signup_success”。你认为那个“if”语句中的问题可能是什么？
这是供参考的PHP：
<?php
// Ajax calls this REGISTRATION code to execute
if(isset($_POST["u"])){
// CONNECT TO THE DATABASE
include_once("php_includes/db_conx.php");
// GATHER THE POSTED DATA INTO LOCAL VARIABLES
$u = preg_replace('#[^a-z0-9]#i', '', $_POST['u']);
$e = mysqli_real_escape_string($db_conx, $_POST['e']);
$p = $_POST['p'];
$g = preg_replace('#[^a-z]#', '', $_POST['g']);
// GET USER IP ADDRESS
$ip = preg_replace('#[^0-9.]#', '', getenv('REMOTE_ADDR'));
// DUPLICATE DATA CHECKS FOR USERNAME AND EMAIL
$sql = "SELECT id FROM users WHERE username='$u' LIMIT 1";
$query = mysqli_query($db_conx, $sql);
$u_check = mysqli_num_rows($query);
// -------------------------------------------
$sql = "SELECT id FROM users WHERE email='$e' LIMIT 1";
$query = mysqli_query($db_conx, $sql);
$e_check = mysqli_num_rows($query);
// FORM DATA ERROR HANDLING
if($u == "" || $e == "" || $p == "" || $g == ""){
echo "The form submission is missing values.";
exit();
} else if ($u_check > 0){
echo "The username you entered is alreay taken";
exit();
} else if ($e_check > 0){
echo "That email address is already in use in the system";
exit();
} else if (strlen($u) < 3 || strlen($u) > 16) {
echo "Username must be between 3 and 16 characters";
exit();
} else if (is_numeric($u[0])) {
echo 'Username cannot begin with a number';
exit();
} else {
// END FORM DATA ERROR HANDLING
// Begin Insertion of data into the database
// Hash the password and apply your own mysterious unique salt
$p_hash = md5($p);
// Add user info into the database table for the main site table
$sql = "INSERT INTO users (username, email, password, gender, ip, signup, lastlogin, notescheck) VALUES('$u','$e','$p_hash','$g','$ip',now(),now(),now())";
$query = mysqli_query($db_conx, $sql);
$uid = mysqli_insert_id($db_conx);
// Establish their row in the useroptions table
$sql = "INSERT INTO useroptions (id, username, background) VALUES ('$uid','$u','original')";
$query = mysqli_query($db_conx, $sql);
// Create directory(folder) to hold each user's files(pics, MP3s, etc.)
if (!file_exists("user/$u")) {
mkdir("user/$u", 0755);
}
//Email the user their activation link
//$to = "$e";
// $from = "auto_responder@dilingle.com";
// $subject = 'yoursitename Account Activation';
// $message = '<!DOCTYPE html><html><head><meta charset="UTF-8"><title>Dilingle Message</title></head><body style="margin:0px; font-family:Tahoma, Geneva, sans-serif;"><div style="padding:10px; background:#333; font-size:24px; color:#CCC;"><a href="http://www.dilingle.com"><img src="http://www.yoursitename.com/images/logo.png" width="36" height="30" alt="yoursitename" style="border:none; float:left;"></a>yoursitename Account Activation</div><div style="padding:24px; font-size:17px;">Hello '.$u.',<br /><br />Click the link below to activate your account when ready:<br /><br /><a href="http://www.yoursitename.com/activation.php?id='.$uid.'&u='.$u.'&e='.$e.'&p='.$p_hash.'">Click here to activate your account now</a><br /><br />Login after successful activation using your:<br />* E-mail Address: <b>'.$e.'</b></div></body></html>';
// $headers = "From: $from\n";
// $headers .= "MIME-Version: 1.0\n";
// $headers .= "Content-type: text/html; charset=iso-8859-1\n";
// mail($to, $subject, $message, $headers);
echo "signup_success";
exit();
}
exit();
}
?>
就像我说的，PHP 脚本末尾的“signup_success”肯定会触发，但上面的 JS 不会正确评估它。
提前致谢！