JAVA, JAVA Applets, and JavaScript Prof. Hele Mai Haav: CIUE, Fall*2000 JAVA, JAVA Applets, and JavaScript

Java, Java Applets The Java programming language is developed by Sun Microsystems. Bill Joy planted the seeds of Java in 1990. Main features: Network based Platform independent Syntax is based on C++ ( C++ minus minus as said by James Gosling)

Java virtual Machine environment Source Code Byte Code Unix PC Mac

A Java applet is a compiled Java program, composed of classes just like any Java program. The Java compiler does not directly translate the Java source code into binary code but into so called Java byte code. This byte code is platform independent and can be executed without modification on all platforms that support Java. A Java interpreter developed for a particular platform is used to execute the byte-code on the target platform. A so-called Java Virtual Machine is used to execute the Java byte-code on the target platform.

Java applications and applets Java Virtual Machine Windows Intel Sparc PowerPC NetworkC Solaris MacOS JavaOS

The basic principle of Java WWW Server Java enabled WWW browser HTML page Java Byte-code Java Compiler Java Source code Java Virtual Machine Byte code interpreter Network HTML data HTML Applet Java Applet

JavaScript JavaScript is Netscape's cross-platform, object-based scripting language for client and server applications. Using JavaScript you can create dynamic Web pages. Java is not JavaScript!

JavaScript HTML tags for JavaScript An example: <SCRIPT> function update (Form) { alert ("form being updated" } </SCRIPT>

JavaScript To learn more about JavaScript see http://javascript.internet.com or http://javascriptsource.com Find there free resource of "Cut&Paste" examples of Java scripts for your web pages. You find JavaScript Guide at http://developer.netscape.com/docs/manuals/communicator/jsguide4/