The function Operator

Besides the Function object, JavaScript also supports a function operator . Following the lead of languages such as Perl and Java, the function operator enables you to define a function without a namethat is, an anonymous function. Here's the syntax of this statementnote how much this works like just assigning a function definition to a variable:

 var  variableName  = function([  parameter1  [,  parameter2  ...[,  parameterN  ]]])  {  functionBody  }

As you see in Table 3.14, the function operator is fairly recent.

Table 3.14. The function Operator

Operator	NS2	NS3	NS4	NS6	IE3a	IE3b	IE4	IE5	IE5.5	IE6
`function`				x					x	x

The syntax for using this operator is much like that for using the Function object. Here's an example putting this operator to work, where I'm setting up a function to double the number you pass it, and assigning that function to a variable named doubler :

(Listing 03-15.html on the web site)

 <HTML>      <HEAD>          <TITLE>              Passing Data to Functions          </TITLE>      </HEAD>      <BODY>          <H1>Passing Data to Functions</H1>          <SCRIPT LANGUAGE="JavaScript">              <!--                 var doubler = function(operand1) {return 2 * operand1}                  document.write("2 * 10 = " + doubler(10))              // -->          </SCRIPT>      </BODY>  </HTML>

Figure 3.12 shows the results of this code.

Figure 3.12. Using the `function` operator.

graphics/03fig12.gif

The function Operator