Simple form validation

checkbox validation

[benji]

I'm a complete php virgin, but have managed to download and use the following script to work perfectly.
I would like to know how to add a validation for a checkbox (must be ticked).
Hope someone can help me.

SCRIPT:

<?php
if(isset($_POST['email'])) {

// EDIT THE 2 LINES BELOW AS REQUIRED
$email_to = "myemail";
$email_subject = "whatever";

function died($error) {
// your error code can go here
echo "We are very sorry, but there are problems with the form you submitted. ";
echo "These errors appear below.<br /><br />";
echo $error."<br /><br />";
echo "Please go back and fix these errors.<br /><br />";
die();
}

// validation expected data exists
if(!isset($_POST['name']) ¦¦
!isset($_POST['surname']) ¦¦
!isset($_POST['email']) ¦¦
!isset($_POST['comments'])) {
died('We are sorry, but there appears to be a problem with the form your submitted.');
}

$first_name = $_POST['name'];
$last_name = $_POST['surname'];
$email_from = $_POST['email'];
$comments = $_POST['comments'];

$error_message = "";
$email_exp = "^[A-Z0-9._%-]+@[A-Z0-9.-]+\.[A-Z]{2,4}$";
if(!eregi($email_exp,$email_from)) {
$error_message .= 'The Email Address you entered does not appear to be valid.<br />';
}
$string_exp = "^[a-z .'-]+$";
if(!eregi($string_exp,$first_name)) {
$error_message .= 'The First Name you entered does not appear to be valid.<br />';
}
if(!eregi($string_exp,$last_name)) {
$error_message .= 'The Last Name you entered does not appear to be valid.<br />';
}
if(strlen($comments) < 2) {
$error_message .= 'The Comments you entered do not appear to be valid.<br />';
}

if(strlen($error_message) > 0) {
died($error_message);
}
$email_message = "Form details below.\n\n";

function clean_string($string) {
$bad = array("content-type","bcc:","to:","cc:","href");
return str_replace($bad,"",$string);
}

$email_message .= "First Name: ".clean_string($first_name)."\n";
$email_message .= "Last Name: ".clean_string($last_name)."\n";
$email_message .= "Email: ".clean_string($email_from)."\n";
$email_message .= "Comments: ".clean_string($comments)."\n";

// create email headers
$headers = 'From: '.$email_from."\r\n".
'Reply-To: '.$email_from."\r\n" .
'X-Mailer: PHP/' . phpversion();
@mail($email_to, $email_subject, $email_message, $headers);
?>

<!-- include your own success html here -->

<?
}
?>

[optik]

you set the value of a check box like this

<input name='name' type='checkbox' id='id' value='true' >

The value can be set to anything and if it isn't checked the value will be empty

[rocknbil]

If a checkbox is checked, it will be present in $_POST. If not, it won't. So all you need is

if (isset($_POST['my-checkbox'])) { // some action }

[d40sithui]

Checkboxes are handled almost like all your inputs.
First insert the checkbox(es) inside your <form> and </form> tags. You could have something like this <input type="checkbox" name="mybox" value="1">.

//checks if checkbox with name "mybox" was checked
if (isset($_POST['mybox'])){

}

//checks value if checkbox with name "mybox"
if($_POST['mybox'] == $someValue){

}

//assigns checkbox value to a variable
$mybox = $_POST['mybox'];