The typical place to define constants is in the wp-config.php file. You will find that many lines defining constants such as, define('XXX', 'xxx'); exist in the file. You can append new lines after them. Note that your lines must be placed before the last line.

Example (wp-config.php):

define ('WPLANG', '');

define ('WPCF7_LOAD_JS', false); // Added to disable JS loading
define ('WPCF7_LOAD_CSS', false); // Added to disable CSS loading

/* That's all, stop editing! Happy blogging. */

/** Absolute path to the WordPress directory. */
if ( !defined('ABSPATH') )
	define('ABSPATH', dirname(__FILE__) . '/');

/** Sets up WordPress vars and included files. */
require_once(ABSPATH . 'wp-settings.php');

The rest of this post describes a variety of constants.

See also:

• Loading JavaScript and Stylesheet Only When it is Necessary
• Restricting Access to the Administration Panel
• Selectable Recipient with Pipes
• CAPTCHA
• File Uploading and Attachment

Change Log

• Incorrect JSON syntax causing conflict with jQuery 1.4 has been fixed
• Some incompatibility issues with IE in admin panel have been fixed
• The logic verifying if a plugin’s JavaScript is loaded has been improved
• Translations for German (Ivan Graf) and Slovak (Patrik Bóna) have been updated
• Translation for Malayalam has been created by RAHUL S.A.

Changelog

• Some other plugins that attempt to include files in inadvisable way were conflicting with Contact Form 7 2.1. A workaround for avoiding these types of issues has been introduced.
• Translations for Chinese (traditional; James Wu), Danish (Georg S. Adamsen), German (Ivan Graf) and Italian (Gianni Diurno) have been updated. Translation for Afrikaans has been newly created by Schalk Burger.
• In addition, this release has a few bug-fixes and improvements.

Changelog

• The required WordPress version has been changed and now requires WordPress 2.8 or higher. If you use WordPress 2.7, you will need to upgrade WordPress.
• New “special mail tags” ([wpcf7.post_id], [wpcf7.post_name], [wpcf7.post_title], and [wpcf7.post_url]) have been introduced.
• The multilingualization functionality has been improved. You are now able to create contact forms in any languages with just a few clicks.
• The Tag Generator’s JavaScript coding has been wholly reconstructed and you can extend it from the additional modules.
• Interoperability with cache plugins (WP Super Cache, etc.) has been improved.
• When known issues are found on your web host, a warning message is shown on the administration panel.
• Uninstall.php file has been added. This will clean up its table from your database when you remove Contact Form 7 from your site.
• Translations for Estonian (by Egon Elbre), German (by Ivan Graf), Hindi (by Ashish) and Italian (by Gianni Diurno) have been updated.

Note that the [wpcf7.post_*] tag has value only when you put the contact form into content of a post or a page. They are not available if the contact form is put inside a sidebar widget.

Using Contact Form 7 in your language

You can translate the administration panel of Contact Form 7 into your language by setting the WPLANG constant. You will find a line defining the WPLANG constant in the wp-config.php file and you can edit this line to change the language. For example, to change it to Japanese (‘ja‘ is its locale code), define it as shown below:

define ('WPLANG', 'ja');

After this is accomplished, your administration panel will show Japanese descriptions. But please note that this doesn’t mean the existing contact forms function in Japanese.

Creating contact form in different languages

With bundled translations, you can create contact forms in different languages very easily. To obtain a translated contact form, simply click the Add new link, and select the language from drop-down menu.

For example, if you are managing a multilingual blog with English and Japanese contact pages, you should create two contact forms — an English contact form for the English contact page and a Japanese contact form for the Japanese contact page.

If you have new translation

If you have created your own language pack, or have an update of an existing one, you can send gettext PO and MO files to me so that I can bundle them into Contact Form 7. You can download the latest POT file from here.

A few days ago, iAssistant LLC published the Beginners Guide (PDF) for Contact Form 7. It contains 50 pages of step-by-step guides with many comprehensible screenshots. I have collaborated with them and have verified all the pages. I think it is a great tool and highly recommend it for those just starting to use Contact Form 7. It is paid content, but you’ll be able to utilize it to save yourself a great deal of time, energy and effort.

[A] Basic header fields (To, From and Subject):

These are basic and necessary message header fields; and you can embed mail tags anywhere in these fields.

[B] Message body:

This is the message body; you can embed mail tags anywhere in this field.

[C] Additional headers:

You can insert additional message header fields here, such as Cc and Bcc. There should be one field per line. You can embed mail tags anywhere in these fields.

[D] File attachments:

If you attach uploaded files to this mail, put mail tags for the uploaded files into this field.

[E] Use of HTML:

By default, plain text is used for the message body. To use HTML, check this box.

[F] Mail (2):

Mail (2) is yet another mail section, except that this is an optional section. Mail (2) works in completely the same manner as Mail. To activate Mail (2), check the Use mail (2) box.

First, you need to activate the Akismet. Akismet is comes automatically installed out-of-the-box so you just need to activate it and set up a WordPress.com API key.

Next, add the following Akismet-related options into the appropriate fields in your form.

• akismet:author
  Add this option to the field that accepts the name of the sender.
  Example: [text* your-name akismet:author]
• akismet:author_email
  Add this option to the field that accepts the email address of the sender.
  Example: [email* your-email akismet:author_email]
• akismet:author_url
  Add this option to the field that accepts the URL of the sender.
  Example: [text your-url akismet:author_url]

When at least one of those options are set (remember, it’s recommended to set all of the options for accurate judgment), Contact Form 7 will send Akismet all of the sender’s input and the information relating to the submitting activity. Akismet will then judge whether this submission is likely to be spam.

If Akismet judges the submission as spam, Contact Form 7 cancels the sending of mails and shows a message that says, “it failed to send the message.” You’ll see an orange border around the response message when it has been judged as spam.

Finally, to make sure it works, you can test it by sending “viagra-test-123″ as name of the sender. This test case will always be judged as spam.

The process is simple. Just insert an acceptance tag into your form like this:

[acceptance accept-this] Check here if you accept these terms.

Due to JavaScript magic, users won’t be able to press the submit button without first checking the box to accept your terms. In addition, you can invert it with an invert option, i.e. allowing users to submit only if they uncheck the checkbox.

Demo

Note: This is a demo. This form doesn’t send a mail practically.

View source of above form:

1) Default
[acceptance accept-this-1] Check here if you accept these terms.

2) Inverted
[acceptance accept-this-2 invert] Uncheck here if you accept these terms.

3) Checked by default + Inverted
[acceptance accept-this-3 invert default:on] Uncheck here if you accept these terms.

[submit "Send"]