Read the Functions section of A Guide to GoScript (along with the rest of that guide) before reading this article.

Defining and Using a Custom Function

You can define your own functions by giving one a unique name:

def myCustomFunction
  # contents of myCustomFunction

You can then call your custom function simply by using its name within another function:

def anotherFunction
  go: https://example.com 
  myCustomFunction

Arguments

An argument is a variable (see GoScript Variables) that you send to a function when you use it.  To define a function that accepts an argument, list the argument(s) after the function name seperated by spaces:

def myCustomFunction myFirstArgument mySecondArgument 
  # This function contains a pair of variables called myFirstArgument and mySecondArgument.
  # When used, these variable will contain whatever values you send to them when you invoke
  # the function.

To send an argument to a function, type the function name followed by a colon and a space, and then a list of values you want to send to the function seperated by spaces. The number and order of values must match the arguments listed in the function definition:

def anotherFunction
  go: https://example.com
  myCustomFunction: someString 123
  # The above command invoked the myCustomFunction function.  In it, myFirstArgument will have
  # the value "someString" and mySecondArgument will have the value 123.

Example

def wrapperFunction
  go: https://www.example.com
  wait for: Example

  replacePageContentsWith: "Hello, World!"
  wait for: Hello, World!

def replacePageContentsWith newContents
  js: document.write("<p>{newContents}</p>");

In this example we define two functions, wrapperFunction and replacePageContentsWith.  replacePageContentsWith takes one argument: newContents.  wrapperFunction invokes replacePageContentsWith and passes it the value "Hello, World!".  replacePageContentsWith then runs, and when it uses its variable newContents, it has the value "Hello, World!".