Select multiple checkboxes in php email form

I'm trying to set up a simple PHP contact form for a website and I need some help modifying the PHP to list multiple items from a select menu and would appreciate the help. I'm a graphic designer, not a developer, so a lot of this is way over my head. This is the problem area here:

HTML:

<form method="post" action="projectplanner.php">
<label>Name*</label><input class="text" name="name" placeholder="Typ hier uw naam">
<label开发者_JAVA百科>Email*</label><input class="text" name="email" type="email" placeholder="Typ hier uw email">
<label>Telefoon*</label><input class="text" name="telefoon" type="tel" placeholder="Telefoon of mobiel">
<label>Organisatie*</label><input class="text" name="organisatie" placeholder="Ik vertegenwoordig..">
<label>Bestaande website (indien van toepassing)</label><input class="text" name="website" placeholder="http://www">
<label>Soort project</label>
<input name="project[]" type="checkbox" value="huisstijl" class="check" />Huisstijl<br />
<input name="project[]" type="checkbox" value="websiteontwerp" class="check"/>Website ontwerp<br />
<input name="project[]" type="checkbox" value="websiteontwikkeling" class="check"/>Website ontwikkeling<br />
<input name="project[]" type="checkbox" value="onlinemarketing" class="check-last"/>Online marketing<br /> 
<label>Beschrijving van uw project</label>
<textarea class="project_text" name="beschrijving" placeholder="Een globale beschrijving. Doelstelling, publiek, concurenten?"></textarea>
<label>Inspiratie</label>
<textarea class="project_text" name="inspiratie" placeholder="Kopieer links naar website / apps / afbeeldingen die u inspireren"></textarea>
<label>* 2+2= ? (Anti-spam)</label>
<input name="human" placeholder="Antwoord">
<input id="submit" name="submit" type="submit" value="Verzend">

PHP:

<?php
$naam = $_POST['naam'];
$email = $_POST['email'];
$telefoon = $_POST['telefoon'];
$organisatie = $_POST['organisatie'];
$website = $_POST['website'];
$beschrijving = $_POST['beschrijving'];
$project = $_POST['project'];
$inspiratie = $_POST['inspiratie'];
$from = 'From: the website'; 
$to = 'someone@somewhere.com'; 
$subject = 'onderwerp';
$human = $_POST['human'];

$body = 
"Van: $name\n 
E-Mail: $email\n 
Telefoon: $telefoon\n 
Organisatie: $organisatie\n 
Website: $website\n 
Project Soort: $project\n 
Omschrijving: $beschrijving\n
Inspiratie: $inspiratie";
if ($_POST['submit'] && $human == '4') {                 
    if (mail ($to, $subject, $body, $from)) { 
    print ("Dank u wel");
    /*echo '<p>Uw bericht is verzonden!</p>';*/
} else { 
    echo '<p>Oeps. Er ging iets fout. Probeer nogmaals.</p>'; 
} 
} else if ($_POST['submit'] && $human != '4') {
/*echo '<p>Uw anti-spam antwoord is niet goed ingevuld.</p>';*/
}

This will list the projects (if any have been checked) like so:

Project Soort: websiteontwerp, websiteontwikkeling, onlinemarketing

<?php
// insure form variables exist
$name         = isset($_POST['name'])         ? $_POST['name']         : '';
$email        = isset($_POST['email'])        ? $_POST['email']        : '';
$telefoon     = isset($_POST['telefoon'])     ? $_POST['telefoon']     : '';
$organisatie  = isset($_POST['organisatie'])  ? $_POST['organisatie']  : '';
$website      = isset($_POST['website'])      ? $_POST['website']      : '';
$beschrijving = isset($_POST['beschrijving']) ? $_POST['beschrijving'] : '';
$inspiratie   = isset($_POST['inspiratie'])   ? $_POST['inspiratie']   : '';
$human        = isset($_POST['human'])        ? $_POST['human']        : '';
$submit       = isset($_POST['submit'])       ? true                   : false;

$project = isset($_POST['project'])
         ? implode(', ', $_POST['project'])     // gather selected checkboxes
         : 'Er geen projecten geselecteerd';    // (Unsure of translation)

$from = 'From: the website'; 
$to = 'someone@somewhere.com'; 
$subject = 'onderwerp';

$body = 
"Van: $name\n 
E-Mail: $email\n 
Telefoon: $telefoon\n 
Organisatie: $organisatie\n 
Website: $website\n 
Project Soort: $project\n 
Omschrijving: $beschrijving\n
Inspiratie: $inspiratie";

if ($submit && $human == '4') {
    if (mail ($to, $subject, $body, $from)) {
        print ("Dank u wel");
        /*echo '<p>Uw bericht is verzonden!</p>';*/
    } else {
        echo '<p>Oeps. Er ging iets fout. Probeer nogmaals.</p>';
    }
} else if ($submit && $human != '4') {
        /*echo '<p>Uw anti-spam antwoord is niet goed ingevuld.</p>';*/
}
?>

If any checkboxes are select when a user sends the form, PHP receives them as an array. The implode() function, pulls all of them together into a comma separated string. Feel free to change the comma (and/or the space following it) to something else if you like.

Hope this helps.

When you add trailing brackets to your field names (ie: project[]), PHP will create an array with the given name, minus the brackets. In your case, the quickest solution would probably be to use a foreach loop to iterate through all the checked boxes like so:

$body = 
"Van: $name\n 
E-Mail: $email\n 
Telefoon: $telefoon\n 
Organisatie: $organisatie\n 
Website: $website\n
Project Soort: ";

foreach ($project as $checkbox) {
    $body .= "$checkbox, ";
}

$body .= "\n 
Omschrijving: $beschrijving\n
Inspiratie: $inspiratie";