User Guide

Executing custom tags 251
However, you can create custom tags that have both a start and an end tag. For example, the
following tag has both a start and an end tag:
<cf_date>
...
</cf_date>
ColdFusion calls the custom tag page date.cfm twice for a tag that includes an end tag: once for
the start tag and once for the end tag. As part of the date.cfm page, you can determine if the call is
for the start or end tag, and perform the appropriate processing.
ColdFusion will also call the custom tag page twice if you use the shorthand form of an end tag:
<cf_date/>
You can also call a custom tag using the cfmodule tag, as shown in the following example:
<cfmodule ...>
...
</cfmodule>
If you specify an end tag to cfmodule, then ColdFusion calls your custom tag as if it had both a
start and an end tag.
Determining if an end tag is specified
You can write a custom tag that requires users to include an end tag. If a tag must have an end tag
provided, you can use
thisTag.HasEndTag in the custom tag page to verify that the user
included the end tag.
For example, in date.cfm, you could include the following code to determine whether the end tag
is specified:
<cfif thisTag.HasEndTag is 'False'>
<!--- Abort the tag--->
<cfabort showError="An end tag is required.">
</cfif>
Determining the tag execution mode
The variable
thisTag.ExecutionMode contains the mode of invocation of a custom tag page.
The variable has one of the following values:
• Start Mode for processing the start tag.
• End Mode for processing the end tag.
• Inactive Mode when the custom tag uses nested tags. For more information, see “Nesting
custom tags” on page 253.
If an end tag is not explicitly provided, ColdFusion invokes the custom tag page only once, in
Start mode.
A custom tag page named bold.cfm that makes text bold could be written as follows:
<cfif thisTag.ExecutionMode is 'start'>
<!--- Start tag processing --->
<B>