PHP Checkbox

nikolai · March 29th, 2004, 04:18 PM

As we've mentioned before, there are many problems with the kind of code you (cyberwolf) posted.

First of all, $License will only exist if 1) register_globals is off *AND* the "License" input field was submitted.

If the checkbox doesn't exist, then $License doesn't exist either. The first time you attempt to access $License, PHP will throw a NOTICE level warning that you're attempting to access the value of a nonexistant variable. This is the "undefined variable" warning you see if error_reporting is E_ALL.

PHP will create this variable and give it a default empty value. For strings, this value is interpreted as the empty string (""). For numbers, it's zero. For booleans, it's FALSE.

Therefore, empty($License) will return true if License wasn't submitted, only because PHP creates it. That also means that assigning the empty string to it is pointless -- PHP already created it with the value of the empty string.

I harp on this issue because PHP has (for a couple years now) uses default configuration settings which would prevent your script from working. As Rich and I have posted countless times, the proper way to do it is:

$License = isset($_POST['License'])? $_POST['License'] : "";

The use of isset() prevents undefined variable warnings from being logged.

Take care,

Nik
http://www.bigaction.org/

emptym · February 5th, 2006, 09:59 AM

Another way to test the checkbox is to also test to see if the form has been submitted. Thus in this example, by default this checkbox is checked, but if the end user un-checks the box and forgets to complete any of the other fields and submits the form then the form is redrawn with the correct status of that checkbox (checked or un-checked).

Code:

<?php

?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; 
charset=iso-8859-1" />
<title>Sign Up For News...</title>
</head>
<body>
<p>Enter your information below to sign up for our news...</p>
<form name="register" id="register" method="post" 
action="<?php echo $_SERVER['PHP_SELF']; ?>">
<label for="fname">First Name:</label> 
<input name="fname" id="fname" type="text" size="32" 
maxlength="32" value="
<?php 
    if(isset($_REQUEST['fname'])&&$_REQUEST['fname']!=""){
        print($_REQUEST['fname']);
    } 
?>" />
<label for="lname">Last Name:</label> 
<input name="lname" id="lname" type="text" size="32" 
maxlength="32" value="
<?php 
    if(isset($_REQUEST['lname'])&&$_REQUEST['lname']!=""){
        print($_REQUEST['lname']);
    } 
?>" />
<label for="email">E-mail Address:</label> 
<input name="email" id="email" type="text" size="32" 
maxlength="32" value="
<?php 
    if(isset($_REQUEST['email'])&&$_REQUEST['email']!=""){
        print($_REQUEST['email']);
    } 
?>" />
<input name="optin" id="optin" type="checkbox" value="yes" 
<?php 
    if( (isset($_REQUEST['submit'])) && (!isset($_REQUEST['optin'])) ){ 
        print ''; 
    }elseif( (isset($_REQUEST['submit'])) && (isset($_REQUEST['optin'])) ){ 
        print 'checked="checked"'; 
    }else{ 
        print 'checked="checked"'; 
    } 
?> /> 
<label for="optin">Yes include me in your e-mailings.</label>
<input name="submit" id="submit" value="Register" 
type="submit" class="submit-button" />
</body>
</html>

alfie · March 1st, 2006, 01:34 PM

hi, JOANNCAE, how was it that you fixed the problem?

im new to php, i have created a form that send info to a database, however i have also put a checkbox in.. when the checkbox is selected all is ok, however the checkboxe returns nothing (neither a name nor a value) if unchecked.

How do i solve this? sorry if this is already mentioned above but it all seems a bit complicated...

(i can supply my code if needed)
Alfie

alfie · March 6th, 2006, 07:36 AM

Anyone?

dbdave · April 23rd, 2006, 06:07 AM

Quote:

quote:Originally posted by alfie
hi, JOANNCAE, how was it that you fixed the problem?

im new to php, i have created a form that send info to a database, however i have also put a checkbox in.. when the checkbox is selected all is ok, however the checkboxe returns nothing (neither a name nor a value) if unchecked.

How do i solve this? sorry if this is already mentioned above but it all seems a bit complicated...

(i can supply my code if needed)
Alfie

Post back your code please... I suspect it's a simple matter of validation.

eda · May 25th, 2006, 04:54 AM

hi guys...
the one that posted by nikolai on 24/09/2003 is similar as what i want... but i need the button "select all" and "unselect all" for the checkbox.one more thing is once we submit, i need the value display in the text area(the text area is in the different window with checkbox form) .. could somebody help me?

thanks in advance...