Can't Get a Variable to Increment after a Post

[Blumengruss]

This is my first post ever on a PHP forum. It's great to feel like there might be some help for my fried brain.

I am working on a site that includes a weekly calendar that will be connected to a database. The script I've written includes a function so that when the weekly calendar loads, it always starts with the last Monday. This is working.

I wrote the script also intending that the visitor can scroll forward or back to another week. This is done by means of a variable called "$scroll". If $scroll = 2, for example, the week that that is displayed is 2 weeks in the future. This is working, too.

I know it sounds dumb, but I can't get the value of $scroll to increment after the visitor slects from a menu how many weeks they want to scroll ahead and then hits the submit button. The value of $scroll goes to whatever is selected, but it never increments. It's like it gets reset to 0 each time there is a post.

I think these are the relevant parts of my code:


$increment=$_POST['increment'];
$scroll=$scroll+$increment;

(code displaying the calendar table...)

<form action="reservations.php" method=post>
Scroll Forward by
<select name="increment">
<option value="1">1 Week</option>
<option value="2">2 Weeks</option>
<option value="3">3 Weeks</option>
<option value="4">4 Weeks</option>
</select>
<input type="submit" name="scroll_forward" value="Go">
</form>


I hope I've explained enough for someone to help.

Many thanks in advance.

[Redline]

Are you storing the value of $scroll in a session variable, or is it included in the uri query?

[Blumengruss]

Hi. Thanks for your reply.

I don't know much about what session variables are, but I don't think I'm using them. I'm just setting those variables I listed to the $_POST value.

[Redline]

Well, if you want to keep using $_POST vars, you'll need to set the $scroll variable as a hidden post var

PHP Code:

<?php
// set scroll equal to scroll + increment
$scroll = $_POST['scroll'] + $_POST['increment'];
?>

(code displaying the calendar table...)

<form action="reservations.php" method=post>
Scroll Forward by
<select name="increment">
<option value="1">1 Week</option>
<option value="2">2 Weeks</option>
<option value="3">3 Weeks</option>
<option value="4">4 Weeks</option>
</select>
<input type="hidden" name="scroll" value="<?=$scroll>">
<input type="submit" name="scroll_forward" value="Go">
</form>

[Blumengruss]

Hi Redline,

Thank you for your follow-up and helpful tips. I tried what you suggested* and it works.

I've also looked into session variables, and can imagine that these would be useful for the intention I have. Would session variables be a better or more "correct" way to do this?

Many thanks,
Eric

*I had to add a ? in one place, so that the hidden input value is:

"<?=$scroll?>" rather than
"<?=$scroll>"

I took a shot in the dark about that, and I don't actually understand that syntax. At first I thought they were opening and closing php tags. Are they? Because when I tried "<?php=$scroll?>" it did not work.

[redhead]

"<?=$scroll?>"

is short form of php script. if you wanted to use the longer form, it would be:

PHP Code:

<?php =$scroll?>

or

PHP Code:

<?php echo "$scroll";?>

Notice the space fromphp to "=".

In your case I would suggest session variables, since I guess you don't want the visitor to snoop on your code, and find out how you increment your scroll value.

[Blumengruss]

Hi redhead,

Thanks so much for for your thoughts on the session variables and also for explaining the tag syntax to me. I've done a bit of eye-rubbing on this and I have to admit that no matter how many times I type it in, I always get a parse error (unexpected "=") when I set the input value this way:

PHP Code:

value=<?php =$scroll?>

or

PHP Code:

value="<?php =$scroll?>"

But it works the other two ways you mention:

PHP Code:

value=<?php echo "$scroll";?>

and

PHP Code:

value="<?=$scroll?>"

and it also works this way:

PHP Code:

value="<?php echo $scroll;?>"

Maybe it's the version of PHP that's running on my host server?

Anyway, your answer and the others I've gotten here have been more than enough to get me going.

Tak skal du have

[sde]

i don't think that <?php =$scroll?> is valid either.

[redhead]

Tak skal du have

You're welcome, no matter where you are, it still remains a small world