PHP5 - Questions about stopping and beginning the next function

I cannot figure out for nothing how you separate different commands or functions. Lets say I want to check to make sure my form had a topic entered and then once it passes it continues on to check the email field for injection. How do I do that? I did not copy my whole script here, just the end of one to the next.

Thanks!

if(!filter_has_var(INPUT_POST, "topic"))
{
echo("You did not enter a topic.");
}
else



function spamcheck($field)


Also, lets say i had a code to remove all html tags and inserted that after the spamcheck was complete. Will the form know to send the email with all these corrections or do I need to output something after each correction is made? I am completely confused and trying to learn this.

PHP code is executed procedurally. All code that exists on its own line without being "inside" something is executed top-to-bottom.

Code that is placed inside curly braces is considered a "block." Blocks of code are only executed if their condition is met. For instance, in your example, the echo will only be executed if the IF statement is true. You can have 50,000 lines inside that IF statement, and none of them will do anything if the IF is false.

Similarly, FUNCTIONs are groups of statements that will only execute if something "calls" that function.

I recommend a good PHP for beginners book, or the PHP manual itself.

-Dan

Thank you. That does help to make better since of things.

Can you help me with this?

Here is my code:

<?php $topic = $_POST['topic'] ; //This checks the subject
if($topic == '')
if(!$topic)
{
echo "You have not entered a subject, please go back and enter a subject.";
}
$message = $_POST['message'] ; //This checks the message
if($message == '')
if(!$message)
{
echo "You have not entered a message, please go back and enter a message.";
}
function spamcheck($field) //filter_var() sanitizes the e-mail
{
$field=filter_var($field, FILTER_SANITIZE_EMAIL); //filter_var() validates the e-mail
if(filter_var($field, FILTER_VALIDATE_EMAIL))
{
return TRUE;
}
else
{
return FALSE;
}
}
if (isset($_REQUEST['email'])) //if "email" is filled out, proceed with sending
//check if the email address is invalid
$mailcheck = spamcheck($_REQUEST['email']);
if ($mailcheck==FALSE)
{
echo "You have not entered a valid email, please press the back button and try again.";
}
else //send email if validation has passed
{
$topic = $_POST['topic'];
$email = $_POST['email'];
$url = $_POST['url'] ;
$message = $_POST['message'] ;
$message1 = $url."\n\n".$message ;
$message2 = $url."\n\n".$message."\n\n".$signature ;
$subject ="***$form Alert*** $topic" ;
$headers ="From: $email";
mail ($to, $subject, $message1, $headers) ;
$subject ="***$company Email Receipt*** $topic" ;
$headers ="From: $webmaster";
mail ($email, $subject, $message2, $headers) ;
print "Your message was sent successfully. The webmaster will be contacting you as soon as possible.";
}
?>


As you can see, I am trying to validate that there is a topic and message entered before sending. However, if one of these fails it still continues to go on down the line and send. It will give the error message but also says Your message was sent.

How can I make it stop if one fails and etc..?

Cleaned up, indented, and commented:
-Dan

You are awesome! The form works great! I am thankful there are people like yourself who are willing to take the time and help others who are wanting to learn.

By looking at this, I figure errors is a set php function like echo correct and doesnt need defining like a variable does? It stops the form or action from continuing. Also, I was wondering if you could explain to me a little about these functions so I can better understand them.

$errors = array(); This looks a little confusing and why the ()?

if ( empty( $message ) ) I am assuming that empty is another set function in PHP and doesn't have to be defined like a variable.

$errors[] = ? What does the [] do here? Being brand new at this I would have put echo '$errors';

What is hard for me to understand is when to use () , [] & the {} symbols.

Just a quick note also, I had the variables $form, $to, $company, & $signature on a separate php file called config.php in case I ever wanted to change these easily. I require this file at the beginning of this file. Is that ok to do?

Nope, I initialized it on the first line.

Bad news: No functions here except the "spamcheck" one you wrote yourself. There are built in functions count(), empty(), and isset(), all of which have well-written entries in the php manual.

Because that's correct. An array is a language construct, it requires the parentheses, even if there's nothing in them.

Yes, empty is a built in function. There are 40,000 of them (yes, really).
$arrayName[] = "something"; appends "something" as a new item to the end of $arrayName. Since $errors was defined at the start of the script as an array, this line takes the new error and puts it on to the "errors array." Arrays are like lists, but much more powerful.



() is for function calls, language constructs, and logical separations.

[] is for arrays.

{} is for string interpolation and control structures.

Example:
You'll get better at it with practice. Get that book. I recommend "Web Database Programming with PHP & MySQL" from O'Reilly Press. It's a little advanced for you though, browse the bookstore.

-Dan

Will do, thanks again for all your help!

This is a great book for beginners. Get the book Dan's recommending, too - it's a good idea to have a couple of different vantage points to reference when you're learning a new language. But, you can work through the exercises in PHP MySQL Web Development, and be productive (not an expert, obviously, but able to find your way around) in PHP within about 2 weeks (as long as you work at it everyday, of course).