javascript - PHP 函数末尾的 0

Question

这直接取自W3Schools教程，但我修改了php文件以使用wordpress钩子(Hook)和js文件来接受两个变量，以便它可以在单个页面中多次使用:https://www.w3schools.com/php/php_ajax_php.asp .

我有以下 gethint.php 文件:

<?php
add_action("wp_ajax_GetHint", "GetHintFunction");
add_action("wp_ajax_nopriv_GetHint", "GetHintFunction");

// embed the javascript file that makes the AJAX request
//wp_enqueue_script( 'my-ajax-request', plugin_dir_url( __FILE__ ) . 'ajaxtest.js', array( 'jquery' ) );
wp_enqueue_script( 'my-ajax-request', plugins_url( '/js/showHint.js', __FILE__ ), array( 'jquery' ) );

// declare the URL to the file that handles the AJAX request (wp-admin/admin-ajax.php)
wp_localize_script( 'my-ajax-request', 'MyAjax', array( 'ajaxurl' => admin_url( 'admin-ajax.php' ) ) );

function GetHintFunction(){
    // Array with names
    $a[] = "Anna";
    $a[] = "Brittany";
    $a[] = "Cinderella";
    ...
    $a[] = "Wenche";
    $a[] = "Vicky";

    // get the q parameter from URL
    $q = $_REQUEST["q"];

    $hint = "";

    // lookup all hints from array if $q is different from ""
    if ($q !== "") {
        $q = strtolower($q);
        $len=strlen($q);
        foreach($a as $name) {
            if (stristr($q, substr($name, 0, $len))) {
                if ($hint === "") {
                    $hint = $name;
                } else {
                    $hint .= ", $name";
                }
            }
        }
    }

    // Output "no suggestion" if no hint was found or output correct values
    echo $hint === "" ? "no suggestion" : $hint;
}

以及以下 showHint.js 文件:

function showHint(str, str2) {
    if (str.length == 0) { 
        document.getElementById(str2).innerHTML = "";
        return;
    } else {
        var xmlhttp = new XMLHttpRequest();
        xmlhttp.onreadystatechange = function() {
            if (this.readyState == 4 && this.status == 200) {
                document.getElementById(str2).innerHTML = this.responseText;
            }
        };
        xmlhttp.open("GET", MyAjax.ajaxurl + "?action=GetHint&q=" + str, true);
        xmlhttp.send();
    }
}

这是 html 页面本身:

<p><b>Start typing a name in the input field below:</b></p>
<form> 
First name: <input type="text" onkeyup="showHint(this.value, 'txtHint1')">
</form>
<p>Suggestions: <span id="txtHint1"></span></p>

<p><b>Type another name in the input field below:</b></p>
<form> 
Last name: <input type="text" onkeyup="showHint(this.value, 'txtHint2')">
</form>
<p>Suggestions: <span id="txtHint2"></span></p>

问题是我的输出在响应末尾有一个零。它看起来是这样的: browser screenshot

我使用了 chrome 的开发人员工具，在 XHR 下，我可以看到 PHP 响应本身在响应末尾包含零。即使我从 js 函数中删除第二个文本框和第二个变量，问题仍然存在，因此问题似乎与 php 文件本身有关。有什么想法吗？

Answer 1

看起来这是一个 WordPress 问题。他们用 die(0) 响应。

https://wordpress.stackexchange.com/questions/116759/why-does-wordpress-add-0-zero-to-an-ajax-response