Validating form values using PHP

Oldcomputer

I have a problem with validating mandatory fields on my form. I have been instructed not to use java script to do this, so I have decided to validate the mandatory information for the form once the user clicks the submit button. In the circumstance when the user hasnt entered all the mandatory fields, I display a text message beside the textbox to denote that the information needs to be entered for this field (the text is in red). Obviously, when they have keyed in a value for the mandatory field no message appears beside the text box.

My problem: How can I reset the Submits buttons value to null to denote a fresh start once the user has keyed in all the values and has moved off to another page? Because once they go back to that page, the error checking I have in place is still active and asks the user to key in all the mandatory fields again.

I am not sure how to tackle this problem and I would greatly appreciate some feedback/suggestions/critisms.

<?php

$firstnamevalid = false;

if ((empty($_POST['Submit']))
{
  $firstnamevalid = false;
}
else
{
    // Validate mandatory fields

    if (isset($_POST['firstname']))
    {
      if (validateMandatory($_POST['firstname']) == true)
      {
        $firstnamevalid = true;
      }
      else
      {
        $firstnamevalid = false;
      }
    }
    else
    {
      $firstnamevalid = false;
    }


  if (($firstnamevalid == true) && etc && etc..)
  {
    $errMsg = false;
    header('Location: gohere.php');
  }
  else
  {
    $errMsg = true;
  }
}

<FORM name="form1" method="post" action="<?php echo $SERVER['PHP_SELF']?>">
<TABLE width="600" cellpadding="0" cellspacing="0" align="center">
<TR valign="center">
<TD width="80" align="left">
<SPAN class="Normal">&nbspFirst Name:</SPAN>
</TD>
<TD width="300" align="left">
<INPUT name="firstname" type="text" class="FormText" id="firstname"
value="<?php if (isset ($POST['firstname'])) echo $_POST
['firstname']; ?>">
<SPAN class="RequiredStar">&nbsp*</SPAN>
</TD>
<TD width="320" align="left">
<?php
if ($firstnamevalid == false)
{
echo '<SPAN class="RequiredStar">&nbspYou haven\'t entered the
first name.</SPAN>';
}
?>
</TD>
<TD>
<INPUT type="submit" name="Submit" value="Submit Information">
</TD>

</TR>
</TABLE>
</FORM>
[/SIZE]

Thanks in advance....

lifeasalounge

I am wondering, why were you told not to use javascript to validate form data?

I have read that Javascript is usually much quicker because the php script is processed by the server so it has to make a round trip.

Does anyone else have any views on this?

Weedpacket

I'm not entirely clear what is being asked for. Are you saying that users may come back to this form sometime later after they have completed it, and you don't them to have to fill the form in again if they do? Using a [man]session[/man] variable may help in this case, which is set on completion to some particular value you can check for (you can store other data here as well, such as the submitted data itself).

Incidentally, you should follow

 header('Location: gohere.php');

with a call to exit, because you want to stop this script from continuing (which it will do unless you tell it to stop).

lifesalounge wrote:
Does anyone else have any views on this?

Client-side validation is faster and saves round trips to the server and back. That is a Good Thing for all concerned.

Server-side validation is necessary because you can't trust the client computer to do what you ask it to.

Conclusion: do both.

iNFERiON

Another way to check if all fields have a value is this:

if($_POST['field1'] != "") {
$field1ok = true;
} else {
$field1ok = false;
}
if($_POST['field2'] != "") {
$field2ok = true;
} else {
$field2ok = false;
}

if(($field1ok==true)&&($field2ok==true)) {
$all_ok = true;
} else {
$all_ok = false;
}

if($all_ok==true) {
header("gohere.php");
exit;
} else {
echo "You did not fill out all the fields";
}

Weedpacket

iNFERiON wrote:
Another way to check if all fields have a value is this:

But it is inferior to the original method, one reason being that it assumes that all fields have values ("" is a value).

Oldcomputer

Weedpacket wrote:
I'm not entirely clear what is being asked for. Are you saying that users may come back to this form sometime later after they have completed it, and you don't them to have to fill the form in again if they do? Using a [man]session[/man] variable may help in this case, which is set on completion to some particular value you can check for (you can store other data here as well, such as the submitted data itself).

I havent done a good job explaining the problem I was getting.

//Boolean Variables used to decide which fields need an error message to denote they havent keyed in a value for that mandatory field.
validatefield1
validatefield2

errmsg = false

if Submit button is empty
//No error messages appear on form
validatefield1 = false
validatefield2 = false etc..
else
//submit button is clicked
//Validate each mandatory field
If field1 is null, empty or contains no data
set validatefield1 = false
else
set validatefield1 = true
end if
Check each field...
end if

if validatefiled1 == true && validatefield2 == true etc
$errmsg = false
header('Location: gohere.php')
exit;
else
$errmsg = true
end if

My problem was that I had commented out the check to see if the errmsg was set, so my validation code kept appearing. ARGH!!! I thought it has something to do with my submit button not resetting itself or something along those lines. shake head

Are you suggesting using session variables? If so, what would be the reason for using that?

Should I be rethinking about the way I should be developing this page, if so, how?

Weedpacket wrote:
Incidentally, you should follow
 header('Location: gohere.php');
with a call to exit, because you want to stop this script from continuing (which it will do unless you tell it to stop).

Yes thankyou, i just forgot to add it here, but I have done that. 🙂

Weedpacket wrote:
Conclusion: do both.

Unfortunately I cannot use javascript.

Thankyou very much for your help. 🙂