Dreamweaver in a Nutshell-Dreamweaver in a Nutshell

21.1 Third-Party Tag Files

The Dreamweaver4/Configuration/ThirdPartyTags folder contains the tag definition files that support ASP, JSP, ColdFusion and PHP tags. (This folder also contains GIF images used as placeholder icons for third-party tags.) The tag definition files are in XML format and can be modified to enhance Dreamweaver's recognition of server-side language tags.

If you are using a server-side language not supported by Dreamweaver, you can create additional tag files that tell Dreamweaver how to read and display third-party tags. (If creating a new tag definition file, give it an .xml extension and place it in the ThirdPartyTag folder.) After creating or updating a tag definition file, restart Dreamweaver to load the new tag definitions. To prevent Dreamweaver from rewriting code in external files, add the third-party script's file extension to the "Never Rewrite Code in File with Extensions" field under Edit Preferences Code Rewriting. See Section 18.4 in Chapter 18 for more information. The formatting options for third-party tags are also controlled by the SourceFormat.txt file, discussed in Section 18.3 in Chapter 18.

21.1.1 <tagspec> Elements

Each tag definition file contains one or more <tagspec> elements. A <tagspec> element does not define a third-party tag (that's up to the third-party language itself), it just tells Dreamweaver how to interpret and display third-party tags. See "Customizing the interpretation of third-party tags" under Help Extending Dreamweaver for additional guidance.

Dreamweaver can interpret two types of third-party tags:

HTML-style tags: So-called normal HTML-style tags are third-party tags that look like typical HTML tags. HTML-style tags may use an opening and closing tag such as <tagname> and </tagname> to enclose data (similar to matching HTML block tags such as <p></p>). HTML-style tags can also be empty. In this case, similar to an HTML <img> tag, they can contain attributes but do not surround content and do not use a closing tag. ColdFusion uses HTML-style tags.
String-delimited tags: String-delimited tags are third-party tags that are delimited by different characters than HTML tags. For example, ASP tags start with <% and end with %>. Therefore, the <tagspec> for string-delimited tags includes the start_string and end_string attributes to specify the delimiters that mark the beginning and end of the tag. Dreamweaver ignores the information between these delimiters. String-delimited tags are similar to empty HTML-style tags (such as <img>) because they do not surround content and do not use a closing tag.

The valid attributes and their values within the <tagspec> differ depending on whether the <tagspec> element describes an HTML-style tag or a string-delimited tag. Dreamweaver uses the attributes to validate or parse the third-party tags (or refrain from doing so, if instructed). The attributes are as follows:

tag_name

Specifies the name for the tag. For HTML-style tags, this attribute is the name of the tag, such as CFABORT. For string-delimited tags, the tag_name is used solely to determine if a Property inspector can edit the tag. (Custom Property inspectors can be written to display and adjust third-party tags, as described in the "A simple Property inspector example" section under Help Extending Dreamweaver.) A Property inspector can indicate that it understands a tag by including its tag_name surrounded by asterisks on its first line of code. For example, because ASP tags use tag_name="asp", Property inspectors that can understand ASP tags should include *asp* on their first line.

tag_type

Specifies whether an HTML-style tag can include contents between its opening and closing tags ("nonempty") or is empty ("empty"). This attribute is ignored for string-delimited tags.

render_contents

Specifies whether to display the tag's contents ("true") or a placeholder icon ("false") in Design view. This attribute is required if you are using tag_type="nonempty", but is ignored for string-delimited tags.

content_model

Specifies where a tag can appear in an HTML file and what type of content it can contain. Four values are possible:

block_model: A tag that can contain block-level elements and appear in the HTML document body only.
head_model: A tag that can contain text and appear in the HTML document head only.
marker_model: A tag that can appear anywhere in the HTML document, such as in the head or body section, and can contain any HTML code this is vaild within that section.
script_model: A tag that contains third-party script information and can be located anywhere in the document. Dreamweaver ignores the content of tags that use this model, such as ColdFusion tags.

start_string

Specifies the starting delimiter for a string-delimited tag, such as "<%" for ASP tags. This attribute is required for string-delimited tags.

end_string

Specifies the ending delimiter for a string-delimited tag, such as "%>" for ASP tags. This attribute is required for string-delimited tags.

detect_in_attribute

Specifies whether Dreamweaver ignores everything between start_string and end_string (for a string-delimited tag) or between opening and closing tags (for an HTML-style tag), even inside attribute names and values. Use true for string-delimited tags. The default is false.

parse_attributes

Specifies whether to parse element attributes. The default is true. Set it to false if the element's attributes don't use the typical name="value" format and thus cannot be parsed by Dreamweaver. For example, the CFIF tag, which implements a logical if statement in ColdFusion, has attributes that aren't name/value pairs and instead look like <CFIF x is 5>. Regardless, this option does not apply to string-delimited tags, whose attributes are never parsed.

icon

Specifies the filename of the GIF image that serves as the placeholder icon in Design view. (The .gif files are typically stored in the ThirdPartyTag folder alongside the tag definition files.)

icon_width

Specifies the icon width, in pixels. Most icons are no more than 18 pixels wide.

icon_height

Specifies the icon height, in pixels. Most icons are no more than 18 pixels high.

21.1.2 Custom Tag Display in Design View

The tag_type and render_contents attributes of the <tagspec> element determine how Dreamweaver displays third-party tags in the Document window's Design view. If tag_type="empty" or render_contents="false", Dreamweaver displays the placeholder icon specified by the icon attribute (depending on the preferences set under View Visual Aids Invisible Elements and Edit Preferences Invisible Elements Server Markup Tags (ASP, CFML, etc.)).

The contents of nonempty tags for which render_contents="true" are displayed in Design view. The content is highlighted according to the preference set under Edit Preferences Highlighting Third-Party Tags.