WebExp2 Experimenter's Manual - School of Informatics - University ...

Figure 17: Available component types and their unique properties.
Type name Property Content
text content the text to show
button content the text for the button
image content the name of a preloaded image resource from the preamble
(see section 5.3 on loading individual images)
input lines how many lines to show in the input — any value greater than 1
will provide a scrollable text box
content
not used; may be implemented later
maxchars
the maximum number of characters which can be typed into the
box
allowed
a list of the characters accepted by the input
restrict
a combination of words representing sets of allowed characters:
digits, letters, symbols
Figure 18: Property tags for visual components. All are optional.
Tag name
width
height
fgcolor
bgcolor
font
Description
the width of the component in pixels
the height of the component in pixels
foreground colour to use for the component
background colour to use for the component
the font in which to display the component’s text
5.8.4 Restricting input
The input response component allows the user to use the arrow keys to navigate, the delete and backspace keys
to edit, the tab key to move between components, and the return key to advance the slide. Any other character
key can be used to provide input, unless you restrict what the subject is allowed to type.
Figure 19 shows the definition for an input component suitable for collecting an age from the participant. It
will not allow the user to advance to the next slide unless it has some input, and will only accept numbers, to a
maximum of three digits. Thus effectively the user has to enter a number between 0 − 999 in order to continue.
Limiting input length You can limit the length of your participant’s input by including the
element. Its content should be an integer defining the maximum number of characters that can be typed into
the input box.
Restriction sets One way of restricting input is to include a restriction set, which defines a set of allowable
characters. Add the element, and as its content include one or more of the following:
• letters – allow alphabetical keys
• digits – allow number keys
• symbols – allow symbols to be typed
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