Validate form then next page

[dunnma]

I have a simple form that I want to validate that the user has entered in information. Right now they fill out the form, then it takes them to the next page where it displays what they entered. They can then either submit, or click back to change their entries. I need to be able to check that they have at least entered information before it gets to the preview page. How can I check first, then if they entered information, go to next page to display it, or if they forgot to fill out one, it reloads the page with an error message?

[stuartc1]

A few option spring to mind. First what about JavaScript ? its the quickest option, you can do it like this:

function val() {
if (document.formname.fieldname.value == "" |
document.formname.fieldname2.value == "") {
alert("You must all fields to continue.");
return false;
}
else {
return true;
}
}

<form name="formname" action="whatever.php" action="post" OnClick="return val();">

Change the 'fieldsname' and 'formname' to match yours.

An other option, if you dont what to use Javascript is this:

Check for empty values on the preview page like -

$err = "";
if ($POST["fieldname"] == "") { $err .=$POST["fieldname"] }
if ($POST["fieldname2"] == "") { $err .=$POST["fieldname2"] }

if ($err !=="")) {
// send the user back passing all the hidden values and the error variable
}

On the form look for the error variable and out put it, also pass the hidden values back into the form values.

HTH🙂

[GBahle]

One thing to note first: PHP is strictly server side, so once the page is displayed, there'll be no more PHP code execution.

This leaves two options:

a) Do the validation with Javascript; thats not really recommended though

b) change your preview page to something like this

function validForm() {
    // do your validation here. You'll probably dont need a function or you'll need more than one, depending on your style of programming
}

if (!validForm) {
    header("Location: yourFormPage.php");
    exit();
}

// Go on with your page like nothing ever happened ;)

It's important to remember that header() only works if there hasnt been any output to the browser yet, that means not even whitespace (something like this will cause an error

<?php

.....

?>

[dunnma]

Originally posted by GBahle
One thing to note first: PHP is strictly server side, so once the page is displayed, there'll be no more PHP code execution.

This leaves two options:

a) Do the validation with Javascript; thats not really recommended though

b) change your preview page to something like this

function validForm() {
    // do your validation here. You'll probably dont need a function or you'll need more than one, depending on your style of programming
}

if (!validForm) {
    header("Location: yourFormPage.php");
    exit();
}

// Go on with your page like nothing ever happened ;)

It's important to remember that header() only works if there hasnt been any output to the browser yet, that means not even whitespace (something like this will cause an error

<?php

.....

?>
------------------------------ [/B]

But if I do the header location thing, will it display the information that they submitted? I know I cna echo the value in each field if the page is refreshed, but if it goes to the next page then comes back I am assuming that it would not have values for the variables.

I have used a class called validator in php. It will do all of the necessary checking and error output. My only probelm with this one is one it passes the test, how do I then send all of the information to the next page so it can be previewed?

By the way an ob() usually fixes the problem with the header error.

Please let me know. Thanks for your help so far.

[GBahle]

Again, some options.

If you're using PHP4, you can simply store the information in a session (just use session_start() at the beginning of each page; variables are passed by $_SESSION["yourVarName"] = ...
in older PHP versions, it's $HTTP_SESSION_VARS or (even less good) session_register()

Second, do all the things (form, validation, preview, submission) on one page, then you wont have to redirect.

Third, store the stuff in a database temporarily.