使用 JavaScript 函数时遇到问题

Question

我正在获取用户输入并将它们存储在 XML 文件中。我正在读取一个 XML 文件并将所有数据存储在 JavaScript 数组中的标签下。这样，如果用户两次输入相同的电子邮件地址，我可以让他们知道该电子邮件已存在于 XML 文件中。这样它就不会在 XML 文件中存储相同的电子邮件两次，因为用户无法注册。但由于某种原因，该功能无法正常工作。我真的需要一些帮助来解决这个问题。我的 XML 文件（storedata.xml）：<?xml version="1.0" encoding="UTF-8"?><document><data><fname>Sammy</fname><lname>Kim</lname><email2>[e-mail]</email2><pass2>123</pass2></data><data><fname>Jimmy</fname><lname>Jabs</lname><email2>[e-mail]</email2><pass2>abc</pass2></data></document>我的PHP代码：<?phpif(isset($_REQUEST['ok'])) {    $xml = new DOMDocument("1.0","UTF-8");    $xml->load("storedata.xml");        $rootTag = $xml->getElementsByTagName("document")->item(0);        $dataTag= $xml->createElement("data");        $name1= $xml->createElement("fname",$_REQUEST['fname']);    $name2= $xml->createElement("lname",$_REQUEST['lname']);    $emailadd= $xml->createElement("email2",$_REQUEST['email2']);    $pwd= $xml->createElement("pass2",$_REQUEST['pass2']);        $dataTag->appendChild($name1);    $dataTag->appendChild($name2);    $dataTag->appendChild($emailadd);    $dataTag->appendChild($pwd);        $rootTag->appendChild($dataTag);        $xml->save("storedata.xml");    }?>我的表单输入：<input type="email" name="email1" placeholder="Email Adress" required="required" class="input-txt" style="width:40%;" id="email1"><input type="email" name="email2" placeholder="Confirm Email Adress" required="required" class="input-txt" style="width:40%;"id="email2"> 我的 JavaScript 代码：<script>var first_email = document.getElementById("email1")  , second_email = document.getElementById("email2")  , password = document.getElementById("password")  , confirm_password = document.getElementById("confirm_password"); 

Answer 1

你可以：

• existingEmails检索电子邮件后创建一个数组。

• 然后在checkEmailExists函数中您将检查电子邮件是否在数组中。

<script>

var first_email = document.getElementById("email1")

  , second_email = document.getElementById("email2")

  , password = document.getElementById("password")

  , confirm_password = document.getElementById("confirm_password");

 

//making an array of the email addresses from the XML file

var request = new XMLHttpRequest();

request.open("GET", "storedata.xml", false);

request.send();

var xml = request.responseXML;

var users = xml.getElementsByTagName("data");

const existingEmails = [];

for(var i = 0; i < users.length; i++) {

    const emailTag = users[i].getElementsByTagName("email2");

    const email = emailTag[0].childNodes[0].nodeValue;

    existingEmails.push(email);

}

//checking if the email already exists

function checkEmailExists() {

    if (existingEmails.includes(first_email.value)) {

        first_email.setCustomValidity("This email address already exists! Please use another one.");

    } else {

        first_email.setCustomValidity('');

    }

}

email1.onchange = checkEmailExists;

function validateMail() {

    if(first_email.value != second_email.value) {

        email2.setCustomValidity("Emails Don't Match");

    } else {

        email2.setCustomValidity('');

    }

}

email2.onkeyup = validateMail;