Java Applet Library "MEW.JAR"

FP Web-Server V2.11

 

 

14.1Introduction to FP Web-Server and the Java Applet "MEW.JAR"

Enhance your HTML Pages with Java Applet Windows:

The Java Applet technology can be used for complex, high-speed, dynamic PLC data visualization in Internet Browser windows. Java applets can help to improve your HTML pages. You only need standard software, the MEW.JAR Java Applet Library and minimal HTML design knowledge.

General:

Java Applets are user application programs written in the programming language Java. These programs are stored together with the HTML files in the Http-Server section on the FP Web-Server unit. The Java Applet file has the file extension .JAR (Java Archive). An Internet browser and a special tag within your HTML page are needed to download the .JAR to the computer. The Java Applet program is then started by the Internet browser and runs on the computer in a secure area ('Sandbox'). Each Java Applet has its own window which can be freely resized and positioned within your HTML page. Parameters within the HTML page can be used to configure the Java Applet functions.

Java Applets Compared to HTML and Java Script:

Normally web pages are designed by using HTML and Java Script (DHTML) code, which allow only very limited dynamic features to be implemented. Moreover, DHTML is not very fast and is not compatible with the various Internet browsers. The programming language Java, which is used to design Java Applets, is a powerful, future-oriented tool for programming huge applications. Java code can run on various computer systems, e.g. Linux and Solaris. Java code runs in a separate, secure area and hence cannot compromise the computer.

The Java Runtime System:

Java program code cannot be executed directly by the computer's CPU (Windows, Linux, Solaris...). Java code is a kind of intermediate or meta code and needs a special software to be interpreted and executed. The required Java interpreter software from the company SUN is called 'Java 2 Runtime Environment', or in short 'JRE'.

For more information on the Java Applet Library, please refer to the online help under the keyword "Java Applet Library" or to the pdf file "JavaAppletLibrary.pdf" on your installation CD-ROM in the sub-folder "JavaApplets".

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