form validation

steyr

Jul 17th 2007, 7:03 am

Hy!

I am new to PHP and tried to perform some form validation. The code shall check if the form contains a value at all!
It does not work out and I am not quite sure if this code could work at all:o!

So- thanks for help!

html>
<head></head>
<body>
<?php
if (!isset($_POST['submit'])) {
?>
<form action= "evaluation.php">
<p>ID Number:<br><input name="ID" type="text" size="30" method= "post"></p>
<input type="submit" value="submit">
</form>
<?php
}
else {

if (!isset($_POST['ID']) || trim($_POST['ID']) == '') {
die("ERROR: please check your input again!!");
}
?>
</body>
</html>

nabil_kadimi

Jul 17th 2007, 8:13 am

Here you are (a simple one)
<body>
<?php
//This will test if at least one field was filled
$initial_state=TRUE;
foreach($_POST as $key=>$value){
if(strlen(trim($value))){
$initial_state=FALSE;
break;
}
}
//This will validate the form values
if(!$initial_state){
$errors = array ();
if(!ereg('^[0-9]{4}$',trim($_POST['ID'])))
$errors['ID Number']='Must be 4 digits';
if(!eregi('^[a-z]{6}$',trim($_POST['code'])))
$errors['Code']='Must be 6 letters';
//this is where you test the values sent by the user
}
//This will print the table containing the erros
if ($errors){
foreach($errors as $field=>$error)
echo "$field: $error<br />\n";
}
//We will display the form the first time or if there are errors in the values sent
if ($initial_state || $errors){
?>
<form method="post" action= "test.php" style="border:solid 1px grey;width:200px;padding:20px;">
ID Number (4 digits):<br>
<input name="ID" type="text" size="30" value="<?php echo $_POST['ID']?>"/>
Code (6 letters):<br>
<input name="code" type="text" size="30" value="<?php echo $_POST['code']?>" />
<input type="submit" value="submit" />
</form>
<?php
}
else{
//For sent without errors
echo "Success !!!";
}
?>
</body>

nabil_kadimi

Jul 17th 2007, 8:22 am

Of course there are some bugs:
try : "<b>This is a bug</b> (with the quote) in a field and hit submit,

Solution: skip the html special characters (< > ' " & /) with a the php string function "htmlsecialchars()".

ecentricNick

Jul 17th 2007, 8:36 am

Hy!

I am new to PHP and tried to perform some form validation. The code shall check if the form contains a value at all!
It does not work out and I am not quite sure if this code could work at all:o!

So- thanks for help!

html>
<head></head>
<body>
<?php
if (!isset($_POST['submit'])) {
?>
<form action= "evaluation.php">
<p>ID Number:<br><input name="ID" type="text" size="30" method= "post"></p>
<input type="submit" value="submit">
</form>
<?php
}
else {

if (!isset($_POST['ID']) || trim($_POST['ID']) == '') {
die("ERROR: please check your input again!!");
}
?>
</body>
</html>

method=post goes in the form attribute not the input attribute. It should read...

<form action= "evaluation.php" method="post">

That's probably why your code doesn't work.

steyr

Jul 17th 2007, 11:18 am

Hy!

Thanks for your answers! Through your help I learn a lot!
With my code I get now (after changing it according to ecentricNick) following message:

Parse error:
syntax error, unexpected $end in C:\Programme\Zend\Apache2\htdocs\user_validation\form.php on line 25

Line 25 is the last line!

regards steyr

nabil_kadimi

Jul 17th 2007, 1:27 pm

That means that php was expecting something...here the last "}" was missing
<html>
<head></head>
<body>
<?php
if (!isset($_POST['submit'])) {
?>
<form action= "evaluation.php">
<p>ID Number:<br>
<input name="ID" type="text" size="30" method= "post">
</p>
<input type="submit" value="submit">
</form>
<?php
}
else {
if (!isset($_POST['ID']) || trim($_POST['ID']) == ''){
die("ERROR: please check your input again!!");
}
}
?>
</body>
</html>

steyr

Jul 18th 2007, 4:27 am

Thanks for reply! How could I be so stupid to forget the }! But still it does not work properly! When I hit the submit button, even when the form contains no value the next page (evaluation.php) appears. So still not input validation!

But I will work on it!

nabil_kadimi

Jul 18th 2007, 2:04 pm

The error was that you forgot to name the <input submit>
so this condition was always true !isset($_POST['submit'])
<html>
<head></head>
<body>
<?php
if (!isset($_POST['submit'])) {
?>
<form action= "test.php" method="post">
<p>ID Number:<br>
<input name="ID" type="text" size="30">
</p>
<input name="submit" type="submit" value="submit">
</form>
<?php
}
else {
if (strlen(trim($_POST['ID']) == 0)){
die("ERROR: please check your input again!!");
}
}
?>
</body>
</html>

steyr

Jul 18th 2007, 11:45 pm

Hy!

I could make the code work but not the way I want it. Now the code works but the form always calls itself- but when the input is correct it should submit the user input to an other file!
But I am coming closer to solution!

regards

<body>
<?php
if (!isset($_POST['submit'])) {
?>
<form action = '<?php $_SERVER['PHP_SELF'] ?>' method = 'post'>
ID Number
<br />
<input type = 'text' name = 'ID'>
<br />

<input type = 'submit' name = 'submit' value = 'Save'>
</form>
<?php
}
else {
// check for required data
// die if absent
if (!isset($_POST['da_id']) || trim($_POST['da_id']) == '') {
die("ERROR: please insert a value");
}
else {

// display message
echo "correct input";
}}
?>
</body>

steyr

Jul 19th 2007, 1:50 am

Hy!

Just solved the whole thing! I just put together the form and the further processing of the data into one file- so it works fine!

Thanks for your help again- it helped a lot!!!

ecentricNick

Jul 19th 2007, 2:02 am

If the input is correct, issue a header redirect to take them to the next page. You'll need to do the test earlier though, as it must be sent before any other output.