User Guide

Chapter 4: ColdFusion Expressions: Operators and Other Constructs 581

Pound Signs

Pound signs (#) have special meaning in ColdFusion. When a CFML application page

is processed, ColdFusion treats text delimited by pound signs differently from plain

text.

Two simple and very important points about pound signs in CFML are:

• Use pound signs to distinguish expressions from plain text.

• When expressions are evaluated, the resulting value is substituted for the

expression text.

For example, to output the current value of a variable named “Form.MyFormVariable,”

you must delimit the variable name with pound signs:

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

When ColdFusion processes an expression, it replaces the text of the expression and

the two pound signs around it with its resulting value. In the example above, the

expression #Form.MyFormVariable# is replaced with whatever value has been

assigned to it.

While the guidelines for using pound signs in CFML are simple, there is still some

possibility for confusion to arise. This is particularly true in cases where expressions

and plain text are mixed together. The following sections provide more details on how

pound signs should be used in CFML.

Pound signs inside CFOUTPUT tags

Expressions containing a single variable or a single function can be used freely inside

CFOUTPUT tags as long as they are enclosed in pound signs.

Value is #Form.MyTextField#

</CFOUTPUT>

The name is #FirstName# #LastName#.

</CFOUTPUT>

Cos(0) is #Cos(0)#

</CFOUTPUT>

If pounds are not used around these expressions, the expression text rather than the

expression value will appear in the output generated by the CFOUTPUT statement.

Note that two expressions inside pound signs can be adjacent to one another, as in

"Mo" and "nk" is #Left("Moon", 2)# #Mid("Monkey", 3, 2)#

</CFOUTPUT>