Exiting and Returning Valuesfrom Functions
Unless instructed otherwise, a function will end naturally when the interpreter finishes executing the last statement in the function’s body. You can, however, terminate a function before the last statement is reached. Additionally, a function can return a result (send back a calculated value) to the code that invoked it. Let’s see how these things work.
Terminating a Function
The
return
statement, which was introduced in
Chapter 6, can be used to terminate a function
and, optionally, to return a result. When the interpreter encounters
a return
statement during a function execution,
it skips any remaining statements in the function. Consider this
example:
function say(msg) { return; trace(msg); // This line is never reached }
The preceding example is not realistic because its
return
statement always causes the function to
end before the trace( )
statement is reached.
Therefore, the return
statement is normally the
last statement in a function body unless it is used inside a
conditional statement. In this example, we use
return
to exit if the password is not correct:
var correctPass = "cactus"; function enterSite(pass) { if (pass != correctPass) { // Exit if the password is wrong return; } // This code is reached only if the password is correct gotoAndPlay("intro"); } enterSite("hackAttack"); // Function will exit prematurely enterSite("cactus"); // Function will end naturally
As its name implies, return
tells the interpreter to return to the ...
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