User Guide

Using Custom Tags 175
Custom tag pages also have access to system data structure called thisTag. The
thisTag structure contains information about the tag and its execution
environment. The
thisTag variable is described in “Executing Custom Tags,” on
page 185.
Using tag attributes
Custom tag attribute values are passed from the calling page to the custom tag page
as name-value pairs.
CFML custom tags support required and optional attributes. Attributes are defined
as name-value pairs. Custom tag attributes conform to CFML coding standards:
• ColdFusion passes any attributes in the Attributes scope.
• Use the cfparam tag with a default attribute at the top of a custom tag to test for
and assign defaults for optional attributes that are passed from a calling page.
• Use the
cfparam tag without a default attribute or a cfif tag with an IsDefined
function at the top of a custom tag to test for required attributes that must be
passed from a calling page.
• Use the Attributes.attribute_name syntax when referring to passed attributes
to distinguish them from custom tag page local variables.
• Attributes are case-insensitive.
• Attributes can be listed in any order within a tag.
• Attribute = value pairs for a tag must be separated by a space.
• Passed values that contain spaces must be enclosed in double-quotes.