We recommend to protect your form agains bots using a captcha.
A "Captcha" is a challenge-response test to ensure, that the form is filled out by a human and not by a machine (bot). The program includes multiple captcha styles. e.g.
There is an input field below the captcha image, in which the user should enter the 5 chars. If the user did not enter the right characters, then an error message will be shown and a new ramdom captcha code will be generated. The script will generate a random captcha code and captcha image each time the form will be displayed.
- No cookies required
- No third party plug-ins required
- No database required
- No fonts required
(The images and script code is included in the single php file generated by the program.)
- Captcha code will be saved on the server (using php SESSIONS)
The user cannot submit the form multiple times, e.g. using the browsers back button (A new random captcha code will be created if the user tries to submit the page again.) A random captcha code will be generated each time a form page will be displayed You can use one of the included captcha styles or let the php script randomize the captcha styles.
- All characters are uppercase in the captcha image, but it will also
accept lower case characters in the response.
- The captcha/script uses the GD php extension, which should be present on most php installations.
Important: A captcha will not give you 100% security. It cannot protect your form against a highly sophisticated attack, but it will block most spam bots and makes life a bit easier.
Captcha Self-Referential URL for php include
The following section is only important if you are using php include and the captcha image shows a broken image!
The captcha image will be created by the same php script, which generates the form. This means there is a self-reference in the generated HTML code with a parameter to create the captcha image. The script can create the self-referential URL itself in most cases, but some providers or CMS are using a mix of virtual and real paths, so that the "auto" function cannot work.
You can specify the "Captcha
Self-Referential URL" in the "Form Properties -> Style and Layout -> Input
Elements" as absolute or relative URL.
e.g. webform.php or folder/webform.php or http://www.yourdomain.tld/folder/webform.php
Please make sure, that you specify the URL to the
include php file - not to the host php file.
e.g. if you use <?php include "mywebform.php"> to include the mywebform.php, then you should enter "mywebform.php" as self-referential URL;
if you use <?php include "/folder/mywebform.php"> to include the mywebform.php, then you should enter "/folder/mywebform.php" as self-referential URL
You can also use the full URL, e.g. https://www.mydomain.tld/folder/webform.php
If you are using a Content Management System (CMS) like e.g. Wordpress, Typo3 or Joomla, then you need to install an extension, which allows to include custom php code first.
Please refer to the documenation of the extension for the correct syntax - a simple "php include might" not work!