键入php时验证文本框[关闭]

Question

I am having a form with a text input field. The text input need to be validated simultaneously when the user enters the data.

<form method="post" action="Newsletter/tester.php">
    <label for="email">email</label>
    <input type="text" name="email" placeholder="Enter your email  *" maxlength="50" required>
    <input type="submit" value="test">
</form>

The input email textbox should be validated on the server side, but I don't have any idea about validating the text field while typing.

Is there any way to do it using php script?

Answer 1

If you are willing to use jQuery and PHP, here's an exemple of what you can do:

HTML

<form action="Newsletter/tester.php" method="post">
    <input type="email" name="email" id="email-input">
    <button type="submit">Send</button>
    <br/>
    <span id="email-validate">Waiting for user input...</span>
</form>

jQuery

jQuery(function($) {

    // When the user types something in the input
    $('#email-input').on('keyup', function(e) {

        // set the variables
        var $input = $(this)
        ,   value  = $input.val()
        ,   data   = {
                email: value   
        };

        // perform an ajax call
        $.ajax({
            url: 'my/validator.php', // this is the target
            method: 'get', // method
            data: data, // pass the input value to server
            success: function(r) { // if the http response code is 200
                $('#email-validate').css('color', 'green').html(r);
                $('button').removeAttr('disabled');
            },
            error: function(r) { // if the http response code is other than 200
                $('#email-validate').css('color', 'red').html(r);
                $('button').attr('disabled', 'disabled');
            }

        });
    });

});

PHP (>= 5.4)

<?php
if(isset($_GET['email'])) {
    $email = $_GET['email'];

    if(filter_var($email, FILTER_VALIDATE_EMAIL)) {
        http_response_code(200);
        echo 'The email '.$email.' is valid';
    } else {
        http_response_code(412);
        echo 'The email '.$email.' is not valid';
    }
}