如何在不使用jQuery但使用纯Javascript的情况下使用AJAX提交此表单

我四处张望，我所能找到的就是关于jQuery的信息。

在SO的伟大思想者的大力帮助下，我终于完成了表单验证（目前仅是客户端，但这是因为它是任务）。我现在需要使用AJAX将表单提交到PHP文件。

我的要求是验证它是通过AJAX调用的，验证所有必填字段都有值，并返回成功状态，包括处理该服务器的时间。

JS小提琴

form动作现在是空的以进行测试，但最终将使用下面的代码调用form.php。

的HTML

<form id="contact" name="contact" onsubmit="return validateFormOnSubmit(this)" action="" method="post">
    <div>
        <label>First Name</label>
        <input placeholder="First Name" type="text" name="name" id="name" tabindex="1" autofocus />
        <div id="name-error" class="error"></div>
    </div>
    <div>
        <label>Nickname</label>
        <input placeholder="Nickname" type="text" name="nickname" id="nickname" tabindex="2" autofocus />
    </div>
    <div>
        <label>Email</label>
        <input placeholder="Email" type="email" name="email" id="email" tabindex="3" autofocus />
        <div id="email-error" class="error"></div>
    </div>
    <div>
        <label>Phone</label>
        <input placeholder="Phone" type="tel" name="phone" id="phone" tabindex="4" autofocus />
        <div id="phone-error" class="error"></div>
    </div>
    <div>
        <label>I prefer</label>
        <input type="radio" name="pet" id="Dogs" tabindex="5" autofocus />Dogs
        <input type="radio" name="pet" id="Cats" tabindex="6" autofocus />Cats
        <input type="radio" name="pet" id="Neither" tabindex="7" autofocus />Neither
        <div id="pet-error" class="error"></div>
    </div>
    <div>
        <label>My favorite number between 1 and 50</label>
        <input placeholder="Favorite number between 1 and 50" type="text" name="number" id="number" tabindex="8" autofocus />
        <div id="number-error" class="error"></div>
    </div>
    <div>
        <label>Disclaimer</label>
        <input type="checkbox" name="disclaimer" id="disclaimer" tabindex="9" autofocus />I confirm that all the above information is true.
        <div id="disclaimer-error" class="error"></div>
    </div>
    <div>
        <button type="submit" name="submit" id="submit" tabindex="10">Send</button>
    </div>
</form>

JS

function validateFormOnSubmit(contact) {
    reason = "";
    reason += validateName(contact.name);
    reason += validateEmail(contact.email);
    reason += validatePhone(contact.phone);
    reason += validatePet(contact.pet);
    reason += validateNumber(contact.number);
    reason += validateDisclaimer(contact.disclaimer);

    console.log(reason);
    if (reason.length > 0) {

        return false;
    } else {
        return false;
    }
}

// validate required fields
function validateName(name) {
    var error = "";

    if (name.value.length == 0) {
        name.style.background = 'Red';
        document.getElementById('name-error').innerHTML = "The required field has not been filled in";
        var error = "1";
    } else {
        name.style.background = 'White';
        document.getElementById('name-error').innerHTML = '';
    }
    return error;
}

// validate email as required field and format
function trim(s) {
    return s.replace(/^\s+|\s+$/, '');
}

function validateEmail(email) {
    var error = "";
    var temail = trim(email.value); // value of field with whitespace trimmed off
    var emailFilter = /^[^@]+@[^@.]+\.[^@]*\w\w$/;
    var illegalChars = /[\(\)\<\>\,\;\:\\\"\[\]]/;

    if (email.value == "") {
        email.style.background = 'Red';
        document.getElementById('email-error').innerHTML = "Please enter an email address.";
        var error = "2";
    } else if (!emailFilter.test(temail)) { //test email for illegal characters
        email.style.background = 'Red';
        document.getElementById('email-error').innerHTML = "Please enter a valid email address.";
        var error = "3";
    } else if (email.value.match(illegalChars)) {
        email.style.background = 'Red';
        var error = "4";
        document.getElementById('email-error').innerHTML = "Email contains invalid characters.";
    } else {
        email.style.background = 'White';
        document.getElementById('email-error').innerHTML = '';
    }
    return error;
}

// validate phone for required and format
function validatePhone(phone) {
    var error = "";
    var stripped = phone.value.replace(/[\(\)\.\-\ ]/g, '');

    if (phone.value == "") {
        document.getElementById('phone-error').innerHTML = "Please enter a phone number";
        phone.style.background = 'Red';
        var error = '6';
    } else if (isNaN(parseInt(stripped))) {
        var error = "5";
        document.getElementById('phone-error').innerHTML = "The phone number contains illegal characters.";
        phone.style.background = 'Red';
    } else if (stripped.length < 10) {
        var error = "6";
        document.getElementById('phone-error').innerHTML = "The phone number is too short.";
        phone.style.background = 'Red';
    } else {
        phone.style.background = 'White';
        document.getElementById('phone-error').innerHTML = '';
    }
    return error;
}

function validatePet(pet) {
    if ((contact.pet[0].checked == false) && (contact.pet[1].checked == false) && (contact.pet[2].checked == false)) {
        document.getElementById('pet-error').innerHTML = "Pet required";
        var error = "2";
    } else {
        document.getElementById('pet-error').innerHTML = '';
    }
    return error;
}

function validateNumber(number) {
    var num = document.forms["contact"]["number"];
    var y = num.value;
    if (!isNaN(y)) {

        //alert('va');

        if (y < 0 || y > 50) {
            //Wrong
            number.style.background = 'Red';
            document.getElementById("number-error").innerHTML = "Must be between 0 and 50.";
            var error = "10";
        } else {
            //Correct
            number.style.background = 'White';
            document.getElementById("number-error").innerHTML = "";
        }
        return error;
    } else {
        document.getElementById("number-error").innerHTML = "Must be a number.";
        var error = "3";
    }
    return error;
}

function validateDisclaimer(disclaimer) {
    var error = "";

    if (document.getElementById("disclaimer").checked === false) {
        document.getElementById('disclaimer-error').innerHTML = "Required";
        var error = "4";
    } else {
        document.getElementById('disclaimer-error').innerHTML = '';
    }
    return error;
}

的PHP

<?php
$name = $_POST['name'];
$email = $_POST['email'];
$from = 'From: TangledDemo'; 
$to = '[email protected]'; 
$subject = 'Hello';
$message = "This is a message.";

if ($_POST['submit']) {              
    if (mail ($to, $subject, $message)) { 
        echo '<p>Your message has been sent!</p>';
} else { 
    echo '<p>Something went wrong, go back and try again!</p>'; 
} 
}
?>

谢谢！