In addition to the Arguments scope, each function can have a number of variables that exist only inside the function, and are not saved between times the function gets called. As soon as the function exits, all the variables in this scope are removed.

In CFScript, you create function-only variables with the var statement. Unlike other variables, you never prefix function-only variables with a scope name.

Using function-only variables

Make sure to use the var statement in CFScript UDFs to declare all function-specific variables, such as loop indexes and temporary variables that are required only for the duration of the function call. Doing this ensures that these variables are available inside the function only, and makes sure that the variable names do not conflict with the names of variables in other scopes. If the calling page has variables of the same name, the two variables are independent and do not affect each other.

For example, if a ColdFusion page has a cfloop tag with an index variable i, and the tag body calls a CFScript UDF that also has a loop with a function-only index variable i, the UDF does not change the value of the calling page loop index, and the calling page does not change the UDF index. So you can safely call the function inside the cfloop tag body.

In general, use the var statement to declare all UDF variables, other than the function arguments or shared-scope variables, that you use only inside CFScript functions. Use another scope, however, if the value of the variable must persist between function calls; for example, for a counter that the function increments each time it is called.