This section explains the syntax of the CFScript language.
You enclose CFScript regions inside <cfscript>
and </cfscript>
tags. No other CFML tags are allowed inside a cfscript
region. The following lines show a minimal script:
<cfscript>
a = 2; </cfscript>
CFScript variables can be of any ColdFusion type, such as numbers, strings, arrays, queries, and objects. The CFScript code can read and write any variables that are available in the page that contains the script. This includes all common scope variables, such as session, application, and server variables.
CFScript supports all CFML expressions. CFML expressions include operators (such as +, -, EQ, and so on), as well as all CFML functions. As in all ColdFusion expressions, you must use CFML operators, such as LT, GT, and EQ. You cannot use JavaScript operators, such as <, >, ==, or ++.
For information about CFML expressions, operators, and functions, see Chapter 4, "Using Expressions and Pound Signs".
CFScript supports the following statements:
assignment |
for-in |
try-catch |
function call |
while |
function (function definition) |
if-else |
do-while |
var (in custom functions only) |
switch-case |
break |
return (in custom functions only) |
for |
continue |
|
The following rules apply to statements:
Note: This chapter documents all statements except var
and return
. For information on these statements, see "Defining functions in CFScript," in Chapter 9.
Curly brace characters ({ and }) group multiple CFScript statements together so that they are treated as a single unit or statement. This enables you to create code blocks in conditional statements, such as the following:
if(score GT 0)
{ result = "positive"; Positives = Positives + 1; }
In this example, both assignment statements are executed if the score is greater than 0. If they were not in the code block, only the first line would execute.
You do not have to put brace characters on their own lines in the code. For example, you could put the open brace in the preceding example on the same line as the if
statement, and some programmers use this style. However, putting at least the ending brace on its own line makes it easier to read the code and separate out code blocks.
CFScript has two forms of comments: single line and multiline.
A single line comment begins with two forward slashes (//) and ends at the line end; for example:
//This is a single line comment.
//This is a second single line comment.
A multiline comment starts with a /* marker and continues until it reaches a */ marker; for example:
/*This is a multiline comment.
You do not need to start each line with a comment indicator. This is the last line in the comment. */
The following rules apply to comments:
MyVariable = 12; // Set MyVariable to the default value.
End of my long comment */ foo = "bar";
/*This is a single line comment using multiline format. */
In addition to the names of ColdFusion functions and words reserved by ColdFusion expressions (such as NOT, AND, IS, and so on), the following words are reserved in CFScript. Do not use these words as variables or identifiers in your scripting code:
break |
default |
function |
switch |
---|---|---|---|
case |
do |
if |
try |
catch |
else |
in |
var |
continue |
for |
return |
while |
Although CFScript and JavaScript are similar, they have several key differences. The following list identifies CFScript features that differ from JavaScript:
You cannot include ColdFusion tags in CFScript. However, you can include cfscript
blocks inside other ColdFusion tags, such as cfoutput.
Although you cannot use ColdFusion tags in CFSCript, CFSCript and ColdFusion functions provide equivalents to several commonly-used CFML tags. The following table lists ColdFusion tags with equivalent functions or CFScript statements: