Using pound signs

Pound signs (#) have a special meaning in CFML. When the ColdFusion server encounters pound signs in CFML text, such as the text in a cfoutput tag body, it checks to see if the text between the pound signs is either a variable or a function.

Is so, it replaces the text and surrounding pound signs with the variable value or the result of the function. Otherwise, ColdFusion generates an error.

For example, to output the current value of a variable named Form.MyFormVariable, you delimit (surround) the variable name with pound signs:

<cfoutput>Value is #Form.MyFormVariable#</cfoutput>

In this example, the variable Form.MyFormVariable is replaced with the value assigned to it.

Follow these guidelines when using pound signs:

• Use pound signs to distinguish variables or functions from plain text.
• Surround only a single variable or function in pound signs; for example, #Variables.myVar# or #Left(myString, position)#. (However, a function in pound signs can contain nested functions, such as #Left(trim(myString), position)#.
• Do not put complex expressions, such as 1 + 2 in pound signs.
• Use pound signs only where necessary, because unneeded pound signs slow processing.

The following sections provide more details on how to use pound signs in CFML. For a description of using pound signs to create variable names, see Using pound signs to construct a variable name in assignments

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