Be Careful Using "#" In ColdFusion DE() Expressions

code-1.cfm

<!---
	Set phone and ext. In reality, these values would be
	coming out of a data base or input form (over which we
	do not have control).
--->
<cfset strPhone = "(123) 456-7890" />
<cfset strExt = "128" />

<!---
	Create full phone number complete with base number and
	line extension.
--->
<cfset strFullPhone = (
	strPhone &
	IIF(
		Len( strExt ),
		DE( " x#strExt#" ),
		DE( "" )
		)
	) />


<!--- Output new number. --->
#strFullPhone#

code-2.cfm

<!---
	Set phone and ext. In reality, these values would be
	coming out of a data base or input form (over which we
	do not have control).
--->
<cfset strPhone = "(123) 456-7890" />
<cfset strExt = "##128" />

<!---
	Create full phone number complete with base number and
	line extension.
--->
<cfset strFullPhone = (
	strPhone &
	IIF(
		Len( strExt ),
		DE(
			Replace(
				" x#strExt#",
				"##",
				"####",
				"all"
				)
			),
		DE( "" )
		)
	) />


<!--- Output new number. --->
#strFullPhone#