Elements

---

Types of elements

Elements contain multimedia content, interactive content, or some combination of the two.

As of PennController 1.9, PennController has 21 types of elements, including:

• Text: Text content (multimedia)
• Timer: A timer (interactive)
• Button: A clickable button (multimedia and interactive)

For a complete list of all the elements, see the Elements reference page.

---

Creating an element

Create an element by calling a newX() function, where X is a type of element. There are 21 newX() functions, one for each type of element: newText() creates Text elements, newTimer() creates Timer elements, newButton() creates Button elements, and so on.

All newX() functions have the following syntax:

• The optional first argument is a string and the element’s name, or the element has no name.

  
    @// Option 1: Element has the name "example-name"
    $newX("example-name", ...)
    @
    @// Option 2: Element does not have a name
    $newX(...)
    

• Any other argument(s), indicated by ... in the previous example, depend(s) on the element.

  
    @// Creates a Text element named "text" that contains the string "Hello, world!".
    $newText("text", "Hello, world!")
    @
    @// Creates a Timer element named "timer" that is 1000ms long.
    $newTimer("timer", 1000)
    

  If a newX() function that can take two strings is passed only one string, that string is passed as the argument that is not the element name.

    // Creates a Text element named "apple" that contains the string "orange".
    newText("apple", "orange")
    ,
    // Creates an unnamed Text element that contains the string "apple".
    newText("apple")
  

Elements must be created inside a trial:

@// Incorrect: The 'newX()' function is called outside of a trial
%newX("element-outside-trial")
%newTrial("trial-without-element")
@
@// Correct: The 'newX()' function is called inside a trial
~newTrial("trial-with-element",
~    newX("element-inside-trial")
~)

Element names

To be filled in

---

Referring back to an element

Refer back to an existing element by calling a getX() function, where X is the same type as the element being referred back to. Like the newX() functions, there are 21 different element-referring functions.

• All getX() functions only take one argument, the name of the element being referred back to:

  
    @newTrial("example-label",
    $    newX("element-one")
    @    ,
    @    newX("element-two")
    @    ,
    $    getX("element-one")
    @)
    

• getX() functions can only refer back to elements of the same type:

  
    @// Incorrect: There is no Button element named "hello"
    %newTrial("example-trial-one",
    %    newText("hello", "Hello, world!")
    %    ,
    %    newButton("goodbye", "See you later")
    %    ,
    %    getButton("hello")
    %)
    @
    @// Correct: There is a Text element named "hello"
    ~newTrial("example-trial-two",
    ~    newText("hello", "Hello, world!")
    ~    ,
    ~    newButton("goodbye", "See you later")
    ~    ,
    ~    getText("hello")
    ~)
    

---