Answer

Enable option for weblog

• Navigate to Settings > Feedback : Comments¹.
• Locate the setting for Allow HTML² and check the box to the left to turn the setting on.
• Press the SAVE button to preserve the change.

Limit HTML Tags

The Sanitize feature protects your weblog from malicious code by permitting only certain HTML tags to be used in comments and TrackBack pings. The default set of allowed HTML tags and attributes is:

a href, b, br, p, strong, em, ul, li, blockquote

You can override this setting globally by setting the GlobalSanitizeSpec setting in the mt-config.cgi³ file; and you can override it on a per-weblog basis in your weblog configuration. Note: Unless you know what you're doing, it is recommended that you stick with the defaults.

Override the setting globally

• Download mt-config.cgi from your server in ASCII mode, then open it in a plain text editor.
• Look for this setting:

  # GlobalSanitizeSpec br/,p

• Uncomment the setting⁴, then update the line to reflect the HTML tags you wish to permit. For example, if you wanted to retain all the default settings, but also allow the <u> tag, your setting would look like this:

  GlobalSanitizeSpec a href,b,br/,p,strong,em,ul,li,blockquote,u

• Once you've updated the line, save mt-config.cgi, then upload it back to your server in ASCII mode.

Override the setting on a per weblog basis

• Navigate to Settings > General : Default Weblog Display Settings⁵.
• Locate the setting for Limit HTML Tags⁶ and select the radio button to the left of Use my settings.
• In the field to the right of the setting, enter all the tags you wish to allow. For example, if you wanted to retain all the default settings, but also allow the <u> tag, you would enter this string in the field:

  a href,b,br/,p,strong,em,ul,li,blockquote,u

• Press the SAVE button to preserve the change.

Your visitors should now be able to use HTML when posting comments, subject to the limits you've imposed by your designated settings.

¹ In versions prior to 3.2, navigate to Weblog Configuration > Preferences : Comment Configuration.

² In versions prior to 3.2, the setting is named Allow HTML in Comments.

³ In versions prior to 3.2, the configuration file is named mt.cfg.

⁴ To uncomment a setting means to remove the # from the beginning of the line where it appears.

⁵ In versions prior to 3.2, navigate to Weblog Configuration > Preferences : General Settings.

⁶ In versions prior to 3.2, the setting is named Sanitize Spec.