Indie-Resource.com

Hey guys, here's a simple way of making a Captcha in php to prevent bots from entering your page to spam and make your life miserable.


First off let's make a new page called myowncaptcha.php

We'll need some random words so let's start making them.

<?php

$vocals= array('a','e','i','o','u','y'); // Added "y" for more variety
$letters = array('a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z');


$threechar = $vocals[rand(0,5)] . $letters[rand(0,25)] . $vocals[rand(0,5)];
$twochar = $vocals[rand(0,5)] . $letters[rand(0,25)];
$twochar2 = $vocals[rand(0,5)] . $letters[rand(0,25)];
$fourchar = $vocals[rand(0,5)] . $letters[rand(0,25)] . $vocals[rand(0,5)] . $letters[rand(0,25)];

You can make howmany characters you want.

$fourwords = array("$threechar", "$twochar", "$twochar2", "$fourchar");

$chosenword = $fourwords[rand(0,3)]; // The word they will write to access.

Now we'll write " write the 'numbered' word to access" but remember it has to be exactly as the chosenword variable.

echo "Write the ";

if ($chosenword == $fourwords[0])
{ echo "first "; }

elseif ($chosenword == $fourwords[1])
{ echo "second "; }

elseif ($chosenword == $fourwords[2])
{ echo "third "; }

elseif ($chosenword == $fourwords[3])
{ echo "fourth "; }

echo "word to access <br />";

foreach($fourwords as $value)
{
echo '"' . $value . '", '; // Dont confuse the double quotes, they're for the string.
}

Now let's write the form.

<form method="get" action="checkcaptcha.php">
<input name="captcha" size="8" type="text" />
<input type="submit" value="submit" />
<input name="chosenword" type="text" value="<?php echo $chosenword;?>" style="visibility: hidden;" /><?php //remember that this input still makes some space.?>
</form>

(the input "chosenword" was made to pass the variable through the url, ther're other ways to pass variables and maybe with more efficiency to another php page but this is the way I'd on this tutorial.)

Now lets make the checkcaptcha.php (it could be the reguser.php page instead, or any other page you want your captcha to work.)


<?php
if($_GET['captcha'] != $_GET['chosenword'])
{
echo "<h2>WRONG!!</h2> Write the correct word. ";
echo "<a href='myowncaptcha.php'>Go back!";
}
else
{
echo "LETS ROCK!"; /// put whatever you like. Probably you will use this to access the reguser.php
}

// GOOD LUCK!!
?>

so it will look something like this:

Here are the sources of this lil tutorial:
myowncaptcha.php checkcaptcha.php So as far as bots can't read and analyze you can be sure that this captcha will keep you away from bots.
Good luck!
indie-resource.com Rocks!

Thanks so much for this! Will be implementing this into our site later!! Great tutorial!!

Very nice! I like it Some of the other techniques I have seen rely on asking questions, like "What is the 3rd rock from the sun?". The problem with systems like these is that, sadly, some people won't understand or won't know the answer so they won't be able to register. But this one pretty much guarantees anyone with a first-semester ability in English can get through

It's a pleasure! and i'm glad this will be helpful to you spiritwebb!

Yes jackolantern you're right, for some people you just need to be so obvious! I'm glad you like it!

Very nice Ark! I to will implement this into my registration of HP Destiny!

That's great man !

Hehe i`ve seen this before, it works pretty good. It`s a humanized form of Captcha, much better then typing those f&*ing letters and digits ( where captialised letters count too.. ) to make "sure" you are human. It had it`s best time.

Yeah, i copied this style in http://www.switchonthecode.com, If you want to comment in a tutorial right below you have to use this method.