为什么无法验证AJAX？

是否使用了正确的条件状态来验证我的PHP是通过Ajax调用的？

我用的是： isset($_SERVER['HTTP_X_REQUESTED_WITH']) && strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest'

<?php

$name = $_GET['name'];
$nickname = $_GET['nickname'];
$email = $_GET['email'];
$phone = $_GET['phone'];
$pet = $_GET['pet'];
$number = $_GET['number'];
$disclaimer = $_GET['disclaimer'];
$from = 'From: Test From'; 
$to = 'euteneier@gmail.com'; 
$subject = 'Hello';
$message = "This is a message.";

$date = new DateTime();
$random = rand(1,50);

// Do even if AJAX wasn't used
if ( isset($_GET['name']) && isset($_GET['nickname']) && isset($_GET['email']) && isset($_GET['phone']) && isset($_GET['pet']) && isset($_GET['number']) && isset($_GET['disclaimer']) ) {               
    if (mail ($to, $subject, $message)) { 
        echo "You're information was successfully sent on:" . $date->format('n/j/Y g:i A') . "
";
        if ($number == $random) {
            echo "Your number: $number matches the random number: $random" . "
";
        } else {
            echo "Your number: $number does not match the random number: $random" . "
";
            }
    } 
    if (isset($_SERVER['HTTP_X_REQUESTED_WITH']) && strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest') {
            //requested with Javascript
            echo "Sent via AJAX!" . "
"; //I HAVE TO COMMENT THIS OUT 
    } else { 
        echo "Something went wrong, go back and try again!" . "
"; 
        } 
}

?>

这是对应的Javascript：

function submitFormAjax() {
    var xmlhttp= window.XMLHttpRequest ?
        new XMLHttpRequest() : new ActiveXObject("Microsoft.XMLHTTP");

    xmlhttp.onreadystatechange = function() {
        if (xmlhttp.readyState == 4 && xmlhttp.status == 200)
            alert(xmlhttp.responseText); // Here is the response
    }

    var name = document.getElementById('name').innerHTML;
    var nickname = document.getElementById('nickname').innerHTML;
    var email = document.getElementById('email').innerHTML;
    var number = document.getElementById('number').innerHTML;
    var radio = document.getElementsByName('pet');

        for (var i = 0, length = radio.length; i < length; i++) {
            if (radio[i].checked) {
            // do whatever you want with the checked radio
                var pet = (radio[i].value);

        // only one radio can be logically checked, don't check the rest
        break;
    }
}

    xmlhttp.open("GET","form.php?name=" + name + "&nickname=" + nickname + "&email=" + email + "&phone=" + phone + "&pet=" + pet + "&number=" + number + "&disclaimer=" + disclaimer, true);
    xmlhttp.send();
}

多谢！

I believe X-Requested-With is a header that some JavaScript frameworks send. You're not using a framework so you'll need to add it yourself somehow.

I dont if you found a solution yet, but i see some problems:

i would change:

xmlhttp.open("GET","form.php?name=" + name + "&nickname=" + nickname + "&email=" + email + "&phone=" + phone + "&pet=" + pet + "&number=" + number + "&disclaimer=" + disclaimer, true);

into this:

var uri = encodeURIComponent("form.php?name=" + name + "&nickname=" + nickname + "&email=" + email + "&phone=" + phone + "&pet=" + pet + "&number=" + number + "&disclaimer=" + disclaimer);
xmlhttp.open("GET",uri, true);

since i don't know what horrors (etc. spaces) lurks in the HTML values.

Also this:

    ...
    for (var i = 0, length = radio.length; i < length; i++) {
        if (radio[i].checked) {
        // do whatever you want with the checked radio
            var pet = (radio[i].value);
    ...

You are declaring the variable pet inside a for-loop, which may or may not defined the time you send the request, which efficiently sends an undefined value (if no radio is selected, although i dont know your html setup), thus not-set in the .php, which pet is a required variable in the basic block condition there.

    ...
    var pet = "";   // dumb value, but exist
    for (var i = 0, length = radio.length; i < length; i++) {
        if (radio[i].checked) {
            // do whatever you want with the checked radio
            pet = (radio[i].value);  
    ...

About the condition

isset($_SERVER['HTTP_X_REQUESTED_WITH']) && strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest'

i think you are fine, i'm just using it the same way without problems, yet can be easily mangled, and anything starting with HTTP_x in general. Definitely not use such logic in secure pages.

$_SERVER['HTTP_X_REQUESTED_WITH']

can be present or not in $_SERVER array and also can be sent by you, via javascript (client) or curl (server) in cases it doesnt exist at first.

xmlhttp.setRequestHeader("X-Requested-With", "XMLHttpRequest");
xmlhttp.open(..);