PHP syntax query

[matelot]

<?php
/* if the "submit" variable does not exist, the form has not been submitted - display initial page */
if (!isset($_POST['submit'])) {
?>

<form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post">
Enter your age: <input name="age" size="2">
<input type="submit" name="submit" value="Go">
</form>

<?php
}
else {
/* if the "submit" variable exists, the form has been submitted - look for and process form data */
// display result
$age = $_POST['age'];
if ($age >= 21) {
echo 'Come on in, we have alcohol and music awaiting you!';
}
else {
echo "You're too young for this club, come back when you're a little older";
}
}
?>

I'm slowly getting my head round php (not dissimilar from QBasic in a lot of ways...), but a couple of things in the above script weren't explained in a tutorial:

1. Why does the initial IF statement start with IF, to be followed by an opening brace, and then that piece of script closed? It's like saying, If so-and-so... forget it.

2. Then the third piece of script starts with a closing brace.

3. Therefore, why does an opening and closing brace overlap the end of one script and beginning of another?

Any helpful explanation appreciated.

Cheers

[ScottR]

I'm not sure you can close a PHP block in the middle of am if else statment. I would have to look into that and try it. I would echo the entire form and escape the quotation marks where needed.

The second if else statement is a nested selection structure. Meaning that if submit is never set, the script never gets the else part of the selection structure, therefore never getting to the nested if else statement.

I don't see where anything starts with a closing brace? If you mean the closing brace under "Come on in, we have alcohol and music awaiting you". That is the closing brace for the if age >= 21 part of the script. Then goes to the else part where the user is not 21 of over.

Hope this helps,
Scott

[matelot]

Ending with an opening brace, lines 3 and 4:
{
?>

Lines 11 and 12, starting with a closing brace:
<?php>
}

It's in an online tutorial, and the script runs OK. I've seen it elsewhere as well.

In fact it's here under Part 4: http://www.goodphptutorials.com/track/229

[ScottR]

Ahhhh Ok I see what you mean! That is because the PHP code is interrupted by HTML. So the PHP block has to be closed and reopened. That was why I had mentioned echoing the entire form and escaping the quotation marks. That seems to me to be more of a logical approach (but that's just my opinion).

If the script works, I guess you can interrupt a a selection structure and reopen it.

Not sure if you know what I mean by escaping, but here a quick example though it is not tested.

Code: Select all

<?php
/* if the "submit" variable does not exist, the form has not been submitted - display initial page */
if (!isset($_POST['submit'])) {
echo "
<form action=\"$_SERVER['PHP_SELF']\" method=\"post\">
Enter your age: <input name=\"age\" size=\"2\">
<input type=\"submit\" name=\"submit\" value=\"Go\">
</form>"
}

The \ is the escape character and makes PHP ingnore whatever is after it. This way PHP won't recognize what's wrapped in quotation marks as a string.

Hope this helps,
Scott

[matelot]

Ahhhh Ok I see what you mean! That is because the PHP code is interrupted by HTML. So the PHP block has to be closed and reopened...

This is the bit I was trying to understand because it seems at variance with other forms of programming e.g. closing a block with an opening brace and then opening a block with a closing brace. Seemed a bit bizarre!

Many thanks so far.

[ScottR]

Your welcome. Hope it works out for ya.

Scott