I cant post my textbox value to another page - php

Question

Hi this is my first aplication .It is self explained code. I think I have missed out something I am trying to change some chars to other but I think I couldnt .because I am just getting a blank page
this is control.php
<?php
function donustur($karakter){
$tk=array("ç","ş","ö");
$ik=array("c","s","o");
$ykarakter= str_replace($tk,$ik,$karakter);
return $ykarakter;
}
$ad=donustur($_POST['adi']);
$mesaj=donustur($_POST['mesaj']);
echo "ad : ".$ad;
echo "ad : ".$mesaj;
?>
this is index.php
<form action="control.php" method="post" enctype="text/plain">
adi : <input type="text" value="adi" size="10" /><br />
soyadı<textarea cols="30" rows="30"
wrap="virtual" maxlength="10" name="mesaj"></textarea><br />
<input type="submit" value="submit" />
</form>

Answer 1

You have at least two problems.
First, see the documentation for plain text form data:
Payloads using the text/plain format are intended to be human readable. They are not reliably interpretable by computer
PHP cannot interpret form data submitted as plain text.
Remove the enctype attribute to use the default encoding type (application/x-www-form-urlencoded).
The only time you should specify the enctype is when you are including file inputs in the form, in which case you need to use multipart/form-data.
Second, a form control can only be successful if it has a name. Add a name attribute to your text input.
<input type="text" name="adi" value="adi" size="10">
Finally, even with those problems, I don't think you should get a blank page. (I don't think any of the errors are critical enough to make PHP bail out). You should get output of:
ad : ad :
If you don't, then the odds are that the file is not being processed with PHP at all. Make sure that you are:
Running a web server that supports PHP
Loading the HTML documents by pointing your browser at http://yourserver/ and not something like file:///c:/foo/bar/index.php

Answer 2

I cleaned it up as best I could considering I don't understand the base language. Hope this helps!
control.php
<?php
function donustur($karakter){
$tk=array("ç","ş","ö");
$ik=array("c","s","o");
$ykarakter= str_replace($tk,$ik,$karakter);
return $ykarakter;
}
if (isset($_POST['adi']) $ad = donustur($_POST['adi']);
if (isset($_POST['mesaj']) $mesaj =donustur($_POST['mesaj']);
echo "ad : ".$ad;
echo "ad : ".$mesaj;
?>
index.php
<?php
<form action="control.php" method="post">
adi : <input type="text" value="adi" size="10" /><br />
soyadı: <textarea cols="30" rows="30" wrap="virtual" maxlength="90" name="mesaj"></textarea><br />
<input type="submit" value="submit" />
</form>
?>