PHP, Forms, and Error Checking

[slevytam]

Hello,

I have a complex html page/form that I would like to error check before insertion into my database.

Here is the problem,

I need to display the errors on the same page as form.

When the user clicks submit I process the form and rewrite the html with an error message included. What happens is I lose all the content of the textboxes etc. How can I display an error message without loosing everything the visitor has entered.

Is it possible just to change a variable an then sortof update the page to reflect the var change instead of rewriting all the html?

I hope this is clear,

Thanks,

--SL

[RedDragon]

you can use js for doing that:

<script type="text/javascript" language="javascript">
<!--
function validate(input) {
	if (input.subject.value=="") {
		alert("Please complete the subject field.");
		return false;
	}
}
//-->
</script>

<form method="post" name="somename" method="post" onSubmit="return validate(this)" action="file.php">

<input type="text" name="subject">

[devinemke]

what i generally do is create a custom function that generates the form and use the isset() function to see which fields the user has already entered. when the form validation fails, i echo an error message and then simply re-run the form function which will include the user input. here is very simplified example:

<?
function form ()
{
	echo '
	<form action="' . $_SERVER['PHP_SELF'] . '" method="post">
	name: <input type="text" name="name" value="'; if (isset ($_POST['name'])) {echo $_POST['name'];} echo '"><br>
	email: <input type="text" name="email" value="'; if (isset ($_POST['email'])) {echo $_POST['email'];} echo '"><br>
	<input type="submit" name="submit" value="submit">
	</form>
	';
}

if (!isset ($_POST['submit']))
{
	echo 'all fields are required:';
	form ();
}

if (isset ($_POST['submit']))
{
	if (!$_POST['name'] || !$_POST['email']) {echo 'You forgot to enter fill out all required fields!'; form ();}
	else {echo 'Thank you.  You submitted:<br><br>' . $_POST['name'] . '<br>' . $_POST['email'];}
}
?>

[slevytam]

Thank you,

This sounds great...

Just two more questions...

I guess you can't do this without specifying a value for each form item.

How would you do this for checkboxes and comboboxes. Ie. I'm not sure how to sex the values for those.

Thanks again,

--SL

[devinemke]

if the form has not been submitted the value with equal nothing (""), if the form has been submitted it will equal whatever the user entered.

as for checkboxes, selects, and radios:

<?
function form ()
{
    echo '
    <form action="' . $_SERVER['PHP_SELF'] . '" method="post">
    check1: <input type="checkbox" name="check1" value="checked"'; if (isset ($_POST['check1'])) {echo ' checked';} echo '"><br>
    check2: <input type="checkbox" name="check2" value="checked"'; if (isset ($_POST['check2'])) {echo ' checked';} echo '"><br>
    <input type="submit" name="submit" value="submit">
    </form>
    ';
}

if (!isset ($_POST['submit']))
{
    echo 'please check all boxes:';
    form ();
}

if (isset ($_POST['submit']))
{
    if (!isset ($_POST['check1']) || !isset ($_POST['check2'])) {echo 'You forgot to check all boxes!'; form ();}
    else {echo 'Thank you for checking all boxes';}
}
?>

[slevytam]

Thanks for your reply.

I don't mean to be a pain but how would this work for comboboxes. I could see making it work using a line of php for every list item in the comboxbox. Hopefully this isn't the solution as some comboxes I have hold 100 list items.

Is there any simple solution to setting the selected item in a combobox?

Sorry for the ignorance,

--SL

[devinemke]

the on/off state of comboboxes (or selects in HTML) are the same for checkboxes and radio buttons: using the boolean "checked" attribute in the input tag. if you have many choices for a combobox then i suggest you store all of the choices in an array (or a database) and loop thru to display all of the choices. in your loop, test to see if the variable has been set and is equal to that array index and if so echo "checked". for example:

<?
$choices = array ('choice1', 'choice2', 'choice3');
echo '<select name="choice">';
foreach ($choices as $value)
{
echo '<option'; if (isset ($_POST['choice']) && $_POST['choice'] == $value) {echo ' checked';} echo '>' . $value;
}
echo '</select>';
?>

[slevytam]

My very last question: "I'm so sorry!"

I have been playing for an hour with different if statements etc. but I cannot get this to work for checkboxes when I want them to start out checked. Is there maybe some variable that indicates if the form has been submitted.

I tried something like this:
if($POST['send']=="on") {echo 'checked';} else if(isset($POST['send']) && $_POST['send']!="on"){} else{echo 'checked';}

This doesn't work because isset($_POST['send']) registers as false when a form is submitted with checkbox unchecked.

This is the last question.

Thanks again,

--SL

[devinemke]

to test whether or not the form has been submitted, test the variable that is the name/value pair of the submit button itself. if your form's submit button looks like this:
<input type="submit" name="submit" value="submit the form">
then you can simply do:
if (isset ($_POST['submit'])) {...do something...}

checkboxes, selects and radios are a bit different from other form types (like text) in that if the are not checked then they are not sent to the $POST array. an empty text input will still set an index in the $POST array, it will just be set to blank. an unchecked checkbox will not send anything thing to the $POST array. Because of this difference, when testing for a blank text field you can simply do:
if (!$POST['text']) {echo 'text is blank';}
but that will fail for an unchecked checkbox, instead you must do:
if (!isset ($_POST['checkbox'])) {echo 'checkbox is not checked';}

[slevytam]

Great! Looks like you solved all my current problems.

Really appreciated your help,

--SL

[Hannibal]

Hi,

I've been following this thread and have a couple of issues with a form that I'm testing on the Web. Part of the form processing script I'm using is this:

// # Form Processor parameters
// # Form Processor parameters
if(!$action)
$errors=0;
$error="The following errors occurred while processing your form input.<ul>";
if($ContactName=="" || $Address=="" || $City=="" || $StateorRegion=="" || $PostalCode=="" || $Country=="" || $EmailAddress=="" || $ProjectBudgeted=="" || $ExpectedStartup=="" || $ProjectURL==""){
$errors=1;
$error.="<li>You did not enter one or more of the required fields. Please go back and try again.";
}
if($errors==1) echo $error;
else{
$where_form_is="http".($HTTP_SERVER_VARS["HTTPS"]=="on"?"s":"")."://".$SERVER_NAME.strrev(strstr(strrev($PHP_SELF),"/"));
$message="Contact Name: ".$ContactName."
Organization: ".$Organization."
Address: ".$Address."
Address 2: ".$Address2."
City: ".$City."
State or Region: ".$StateorRegion."
Postal Code: ".$PostalCode."
Country: ".$Country."
Telephone: ".$Telephone."
Fax: ".$Fax."
Email Address: ".$EmailAddress. ; if (!eregi("^{[a-zA-Z0-9_]+@[a-zA-Z0-9-]+.[a-zA-Z0-9-.}+$",} email))"

My question is whether the isset() function can be employed in my form processing script. I have placed the eregi() function here to check email in for demo purposes only; haven't tested it yet.
Also, in my form, I have a comments textarea box. For some reason, it's erroring out when I put it in the required parameters, even though the data is getting recorded in the DB. Are there some specific problems with textarea boxes that would cause this? Otherwise, the script works great.

Thanks

[slevytam]

Not sure if I can help anyone with this stuff yet; however, I believe isset can be used anywhere to determine whether a variable is set.

I use some thing like this:

if(!isset($POST['userName']) | !isset($POST['password'])) {
//If vars are not set
}
else{
//If vars are set
}

[Hannibal]

Well, you have given me a pointer. I assume that I can also use the email validating function in the same context. I'm trying various scenarios now in order to improve this script for future form processing.

Thanks for the input.

[Hannibal]

Hi,

Still working on my form. However, I need a little help in seeing an error in the following:

Form Processor parameters

if (isset ($POST['submit'])) {
$errors=0;
echo $error="The following errors occurred while processing your form input.<ul>";
}
if(!isset($POST['ContactName']) | !isset($_POST['Address'])) {
$errors=1; echo $error.="<li>You did not enter one or more of the required fields.";
}
if($errors==1) echo $error;
else{

The second part of this code generates the error message on opening the page, even though nothing has been entered or submitted.

I've scanned this, as you can imagine, a hundred times and can't find the problem. Can anyone see what's missing or included that may be causing this error to occur? Doesn't affect the processing of the form data to the DB.

Thanks.

[mnewhart]

Hannable, (sorry if is spelled this wrong...)

I noticed in your code:

Form Processor parameters

if (isset ($POST['submit'])) {
$errors=0;
echo $error="The following errors occurred while processing your form input.<ul>";
}
if(!isset($POST['ContactName']) | !isset($_POST['Address'])) {
$errors=1; echo $error.="<li>You did not enter one or more of the required fields.";
}
if($errors==1) echo $error;

else{

you said it was still causing the error message to generate even though nothing had posted. You have the first if statements bracket in the the wrong place. Move it down below the second if statements bracket. Also, set the $errors=0; before the first if statement. I don't know if you had fixed this yet. I was searching for some form validation ideas and found this thread and noticed that no one had replied to your last request. Your code should look like this:

Form Processor parameters

$errors=0;

if (isset ($POST['submit'])) {
echo $error="The following errors occurred while processing your form input.<ul>";
if(!isset($POST['ContactName']) | !isset($_POST['Address'])) {
$errors=1; echo $error.="<li>You did not enter one or more of the required fields.";
}
}
if($errors==1) echo $error;

else{

No need to test for errors if the form has not been submitted yet. Hope this helps.

[Hannibal]

Your reply is well-received and appreciated. And, no, I had not solved it, so your input is very helpful.

I have been working on this form for some time and I've got most of what I need in place now. One more question, what is the best solution to use when a user does error to retain the information they have already inputed?

I read about hidden fields but have not seen any example in these forums what the construction should be. Also, using some construct like @$variable_name, but in researching php.net and these forums, I was unable to locate such information.

Thanks again for checking this out with me. Most users would have just moved on.

[slevytam]

Hello,

I'm not exactly sure what you asking...

"what is the best solution to use when a user does error to retain the information"

Isn't this what the 20 posts have been about. Code was provided for entryfields, radio buttons, and comboboxes.

What else is there?

Good luck,

--SL

[Hannibal]

The code is not working. Consequently, just having [POST] scripted is not necessarily magic. Supplying a complete and detailed response to a query can be.

[mnewhart]

Hannibal,

Sorry I didn't get back to you on this thread. Here is what I am using for a form validator that posts to itself. I found some of these techniques on this forum in my search for form validation. This whole code works 100%... Let me know if it helps.

Put this at the top of your form page and make sure your page ends with .php.

<?php session_start(); ?>

The rest of the form code in my form is seperate because I have built a template around it. Take a look at www.itsasoycandle.com/joinclub.php for the final result.

I may have been a little redundent on the error checking, but I wanted to make sure. I am not a PHP guru by any means. I just have 12 years of programming in VB and about 4 in Java, HTML, ASP. I picked PHP up really fast, and now will use nothing else because of its power and ease of use... Let me know if this worked for you...

Ooops, the text is too long for this board, so I will attach the file...

[Hannibal]

Newhart,

Thanks again for the update. I am someone who has also moved from the VB and ASP env to PHP, and like you would prefer to use nothing else. I'm just really getting started writing my own code. I can hack any code, however.