PHP Drop Down Multi Select_问答_开发者_运维开发者技术经验分享

I am new to the world of coding and PHP. Having picked up some of the basics, I have put a form together. I'm sure there are much efficient ways to code a page however seeing I have put something together with what I have learnt so far, I am having troubling getting past on select a multi-select dropdown after the user has posted the page i.e. to remember what the user selected. Here is my entire code.

<?php
//Process form variables

//Validate if the form has been submitted
if(isset($_POST['submit'])) {

    //Validate if the form elements were completed
    $fname = isset($_POST['fname']) ? $_POST['fname'] : '';
    $lname = isset($_POST['lname']) ? $_POST['lname'] : '';
    $email = isset($_POST['email']) ? $_POST['email'] : '';
    $gender = isset($_POST['gender']) ? $_POST['gender'] : '';
    $updates = isset($_POST['updates']) ? 开发者_C百科$_POST['updates'] : '';
    $media = isset($_POST['media']) ? $_POST['media'] : '';
    $comments = isset($_POST['comments']) ? $_POST['comments'] : '';

    //Place error messages in an array
    $errormsg = array();

    if(empty($fname)) {
            $errormsg[0] = 'Please specify your first name. It\'s blank.';
        }

    if(empty($lname)) {
            $errormsg[1] = 'Please specify your last name. It\'s blank.';
        }

    if(empty($email)) {
            $errormsg[2] = 'Please provide an email address. It\'s blank.';
    }

    if(empty($gender)) {
        $errormsg[3] = 'Please select a gender. It\'s blank.';
    }

    if(empty($updates)) {
        $errormsg[4] = 'Please select how we can contact you. It\'s blank.';
    }

    if(empty($media)) {
        $errormsg[5] = 'Please select where you heard about us. It\'s blank.';  
    }

    if(empty($comments)) {
        $errormsg[6] = 'Please tell us what you think of us. It\'s blank.';
    }

    //Return list of error messages
    foreach($errormsg as $errormsg) {
        echo $errormsg .  '<br />';
    }

    //Debug
    print_r($_POST['media']);
}

?>
<html>
    <head>
        <title>Sample Registration Form</title>
    </head>

    <body>
        <h2>Sample Registration Form</h2>

            <form name="registration" method="post" action="registration.php">
                <div>
                    First Name:  <br />
                    <input type="text" name="fname" value="<?php if(!empty($_POST['fname'])) { echo $fname; } ?>">
                </div>

                <div>
                    Last Name: <br />
                    <input type="text" name="lname" value="<?php if(!empty($_POST['lname'])) { echo $lname ; } ?>">
                </div>

                <div>
                    Email Address: <br />
                    <input type="text" name="email" value="<?php if(!empty($_POST['email'])) { echo $email; } ?>">
                </div>

                <div>
                    Gender: <br />
                    <?php
                    //Generate gender array
                    $gender = array('male', 'female');
                    $countgender = count($gender);

                    for($start=0;$start < $countgender;$start=$start+1) {

                        $status = '';

                        if(isset($_POST['submit'])) {
                            if($_POST['gender'][0] == $gender[$start]) {
                                $status = 'checked';
                                // echo $gender[$start];
                            }
                        }

                        $genderform = '<input type="radio" name="gender[]" value="'. $gender[$start] . '" '. $status. '>' . $gender[$start];
                        echo $genderform;

                    }                       

                        // foreach($gender as $gender) {

                            // $status = '';

                            // if(isset($_POST['submit'])) {

                                // if($_POST['gender'][0] == $gender) {
                                    // $status = 'checked';
                                // }
                            // }

                            // $genderform = '<input type="radio" name="gender[]" value="' .$gender . '" ' . $status .'>'. $gender . '';
                            // echo $genderform;
                        // }
                    ?>
                </div>

                <div>
                    Would you like to receive updates from us? <br />
                    <?php
                    $updates = array(0 => 'newsletter', 1 => 'email', 2 => 'sms');

                    foreach($updates as $updatekeys => $updatevalues) {

                        $status = '';

                        if(!empty($_POST['updates'][$updatevalues]) == $updatevalues) {
                            $status = 'checked';
                            // echo $_POST['updates'][$updatevalues];

                        }

                        echo '<input type="checkbox" name="updates[' . $updatevalues . ']" value="'. $updatevalues. '" '. $status . '>'.$updatevalues;
                    }

                    ?>
                </div>

                <div>
                    How did you hear about us? <br />

                    <select name="media[]" multiple>
                    <?php

                        $media = array(0 => 'internet', 1 => 'pamphlet', 2 => 'brochure');

                        foreach($media as $mediakey => $mediavalue) {

                            $mediaform = '<option value="'. $mediavalue . '">'.$mediavalue.'</option>';
                            echo $mediaform;

                        }
                    ?>
                    </select>
                </div>

                <div>
                    Tell us what you think: <br />
                    <textarea name="comments" cols="50" rows="10"><?php if(!empty($_POST['comments'])) { echo $comments; } ?></textarea>
                </div>

                <div>
                    <input type="submit" name="submit" value="submit">
                </div>
            </form>
    </body>
</html>

EDIT

Guys, I have updated my code to reflect some of the suggestions below. Let me know if the page is better coded. I have not included suggestions such as $start++ just because I am trying to understand what it means. I love to make coding as short as possible but seeing that I am just learning, best to get a good foundation.

<?php
//Initialize session
session_start();

//Generate session id
echo session_id() . '<br />';

//Process form variables

//Validate if the form has been submitted
if(isset($_POST['submit'])) {

    //Validate if the form elements were completed
    $fname = isset($_POST['fname']) ? $_POST['fname'] : '';
    $lname = isset($_POST['lname']) ? $_POST['lname'] : '';
    $email = isset($_POST['email']) ? $_POST['email'] : '';
    $gender = isset($_POST['gender']) ? $_POST['gender'] : '';
    $updates = isset($_POST['updates']) ? $_POST['updates'] : '';
    $media = isset($_POST['media']) ? $_POST['media'] : '';
    $comments = isset($_POST['comments']) ? $_POST['comments'] : '';

    //Place error messages in an array
    $errormsg = array();

    if(empty($fname)) {
            $errormsg[0] = 'Please specify your first name. It\'s blank.';
        }

    if(empty($lname)) {
            $errormsg[1] = 'Please specify your last name. It\'s blank.';
        }

    if(empty($email)) {
            $errormsg[2] = 'Please provide an email address. It\'s blank.';
    }

    if(empty($gender)) {
        $errormsg[3] = 'Please select a gender. It\'s blank.';
    }

    if(empty($updates)) {
        $errormsg[4] = 'Please select how we can contact you. It\'s blank.';
    }

    if(empty($media)) {
        $errormsg[5] = 'Please select where you heard about us. It\'s blank.';  
    }

    if(empty($comments)) {
        $errormsg[6] = 'Please tell us what you think of us. It\'s blank.';
    }

    //Return list of error messages
    foreach($errormsg as $errormsg) {
        echo $errormsg .  '<br />';
    }

    //Debug
    // print_r($_POST['media']);
}

?>
<html>
    <head>
        <title>Sample Registration Form</title>
    </head>

    <body>
        <h2>Sample Registration Form</h2>

            <form name="registration" method="post" action="registration.php">
                <div>
                    First Name:  <br />
                    <input type="text" name="fname" value="<?php if(!empty($_POST['fname'])) { echo $fname; } ?>">
                </div>

                <div>
                    Last Name: <br />
                    <input type="text" name="lname" value="<?php if(!empty($_POST['lname'])) { echo $lname ; } ?>">
                </div>

                <div>
                    Email Address: <br />
                    <input type="text" name="email" value="<?php if(!empty($_POST['email'])) { echo $email; } ?>">
                </div>

                <div>
                    Gender: <br />
                    <?php
                    //Generate gender array
                    $gender = array('male', 'female');
                    $countgender = count($gender);

                    for($start=0;$start < $countgender;$start=$start+1) {

                        $status = '';

                        if(isset($_POST['submit']) && !empty($_POST['gender'])) {
                            $status = in_array($gender[$start], $_POST['gender']) ? 'checked' : '';
                        }

                        $genderform = '<input type="radio" name="gender[]" value="'. $gender[$start] . '" '. $status. '>' . $gender[$start];
                        echo $genderform;

                    }                       

                    ?>
                </div>

                <div>
                    Would you like to receive updates from us? <br />
                    <?php
                    $updates = array(0 => 'newsletter', 1 => 'email', 2 => 'sms');

                    foreach($updates as $updatekeys => $updatevalues) {

                        $status = '';

                        if(isset($_POST['submit']) && !empty($_POST['updates'])) {
                            $status = in_array($updatevalues, $_POST['updates']) ? 'checked' : '';
                        }

                        // if(!empty($_POST['updates'][$updatevalues]) == $updatevalues) {
                            // $status = 'checked';
                            // echo $_POST['updates'][$updatevalues];

                        // }

                        echo '<input type="checkbox" name="updates[' . $updatevalues . ']" value="'. $updatevalues. '" '. $status . '>'.$updatevalues;
                    }

                    ?>
                </div>

                <div>
                    How did you hear about us? <br />

                    <select name="media[]" multiple>
                    <?php

                        $media = array(0 => 'internet', 1 => 'pamphlet', 2 => 'brochure');

                        foreach($media as $mediakey => $mediavalue) {

                            $status = in_array($mediavalue,$_POST['media'])? 'selected' : '';

                            $mediaform = '<option value="'. $mediavalue . '" '. $status .'>'.$mediavalue.'</option>';
                            echo $mediaform;

                        }
                    ?>
                    </select>
                </div>

                <div>
                    Tell us what you think: <br />
                    <textarea name="comments" cols="50" rows="10"><?php if(!empty($_POST['comments'])) { echo $comments; } ?></textarea>
                </div>

                <div>
                    <input type="submit" name="submit" value="submit">
                </div>
            </form>
    </body>
</html>

You can use in_array function to check whether the current $mediavalue in the array of selected $media - but you need to select another name for array with media sources, because it overwrites the $media variable with user selection. For example:

 $mediaTypes = array(0 => 'internet', 1 => 'pamphlet', 2 => 'brochure');
 foreach($mediaTypes as $mediakey => $mediavalue) {
   $mediaform = '<option value="'. $mediavalue . '" '
     . (in_array($mediavalue, $media) ? 'selected' : '') . '>' . $mediavalue.'</option>';
   echo $mediaform;
 }

There are a few recommended minor modifications to you code as well:

you do not need to use numbers in array - it duplicates the default behavior, so $mediaTypes = array(0 => 'internet', 1 => 'pamphlet', 2 => 'brochure'); can be just $mediaTypes = array('internet', 'pamphlet', 'brochure');
when gender is not set, $_POST['gender'] causes notice "Undefined index: gender".
$start=$start+1 can be compacted to $start++;
it is better to reuse the variables with user inputs instead of accessing $_POST directly

Try this:

foreach($media as $mediakey => $mediavalue) {

    $selected=in_array($mediavalue,$_POST['media'])?"selected":"";

    $mediaform = '<option '.$selected.' value="'. $mediavalue . '">'.$mediavalue.'</option>';

    echo $mediaform;

}

based on form output of the dropdown, set a $_SESSION['variable'] the do something like:

if (isset($_SESSION['variable'])) {
// if exists
}
else {
// if doesn't exist
}

you could even include other elseif statements based on different parameters. Then use else as an error handle.

PHP Drop Down Multi Select

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