Pepperl+Fuchs OHV300, Руководство по программированию на JavaScript, Страница: 14 / 94

14
Programming Concepts
3 Programming Concepts
To help the developer create unique applications for the reader, we provide this JavaScript
Programming Guide. The developer can create complex business applications with
prompts and data entry through the OHV300 user interface features (keypad and display
screen).
The features of the programming interface include:

A graphical user interface

Event handlers

Symbol decoding

Host communications

Local data storage

Handheld configuration
In support of these features, the environment defines the following objects:

gui

reader

storage

comm
Using these features, you can create robust, interactive, and sophisticated user
applications.
A script can be made the default application using the configuration utility, or it may be run
from the configuration utility without making it the default.
Note!
The default application allows scripts to be run by host command or configuration code scan;
the command is “|run:scriptName.js” (using your own scriptName).
3.1 Simplicity
The “Hello World!” application is traditionally the first application presented in a
programming guide. It is an easy to code and understand application that illustrates how
the programming environment works.
In its simplest form, the “Hello World!” application in the OHV300 environment sends text
to the display. With the following single line of code, you can display “Hello World!” in the
screen defined by the standard OHV300 gui object (section 4.1).
gui.show(new gui.Text("Hello World!"));
Execution of this script displays the image shown in Figure 1.