<?php
//bad word filter program
$_POST['text']='';

$text = $_POST['text'];
if(isset($_POST['submit']))
{

//Must be at least 3 characters and not more than 20
//The field must be at least 3 characters long

if (strlen($text) < 3)
{
    echo "<center>The field must be at least 3 characters long:
    <a href=\"java script:history.go(-1)\">Go Back</a></center>";  
//Die();
}
//The field cannot contain more than 20 characters
elseif (strlen($text) > 20)
{
    echo "<center>The field cannot contain more than 20 characters:
    <a href=\"java script:history.go(-1)\">Go Back</a></center>";  
//Die();
}
// May not start with a dot
elseif (ereg("^\.",$text))
{
    echo "<center>Invalid Characters:<a href=\"java script:history.go(-1)\">Go Back</a>            </center>";  
//Die();
}
//Text cannot contain a <
elseif (ereg("\<", $text))
{
    echo "<center>Invalid Characters:<a href=\"java script:history.go(-1)\">Go Back</a>          </center>";  
//Die();
}
//Text cannot contain a [
elseif (ereg("\[", $text)) {
    echo "<center>Invalid Characters:<a href=\"java script:history.go(-1)\">Go Back</a></center>";  
//Die();
}
//Text cannot contain a ]
elseif (ereg("\]", $text))
{
    echo "<center>Invalid Characters:<a href=\"java script:history.go(-1)\">Go Back</a></center>";  
//Die();
}
//Text cannot contain "viagra"
elseif (ereg("\viagra", $text))
{
    echo "<center>Invalid Characters:<a href=\"java script:history.go(-1)\">Go Back</a></center>";  
//Die();
}
//Text cannot contain "online"
elseif (ereg("\online", $text))
{
    echo "<center>Invalid Characters:<a href=\"java script:history.go(-1)\">Go Back</a></center>";  
//Die();
}
//Text cannot contain a @
elseif (ereg("\@", $text))
{
    echo "<center>Invalid Characters:<a href=\"java script:history.go(-1)\">Go Back</a></center>";  
//Die();
}
//Text cannot contain "online"
elseif (ereg("\online", $text))
{
    echo "<center>Invalid Characters:<a href=\"java script:history.go(-1)\">Go Back</a></center>";  
//Die();
}
//Text cannot contain a %
elseif (ereg("\%", $text))
{
    echo "<center>Invalid Characters:<a href=\"java script:history.go(-1)\">Go Back</a></center>";  
// Die();
}

echo $text;
}
else
{

?>
<form action="<? $_SERVER['PHP_SELF'] ?>" method="post">
<input type="text"  name="text"><br>
      
    <input type="submit" name="submit" value="demo"><br>
</form>
<?php
}
?>