↑
Main Page

HTML document

Here’s an example applet that makes use of the LiveConnect package:

import java.applet.Applet;

import java.awt.Graphics;

import java.awt.HeadlessException;

import netscape.javascript.*;

public class ExampleApplet3 extends Applet {

public ExampleApplet3() throws HeadlessException {

super();

}

public void paint(Graphics g) {

JSObject window = JSObject.getWindow(this);

JSObject document = (JSObject) window.getMember(“document”);

JSObject location = (JSObject) window.getMember(“location”);

g.drawString(“Title: “ + document.getMember(“title”), 10, 20);

g.drawString(“URL: “ + location.getMember(“href”), 10, 40);

window.eval(“getMessageFromApplet(\”Hello from the Java applet!\”)”);

}

This applet uses the applet’s

paint()

method to interact with the page’s JavaScript. The method begins

by getting references to the window, document, and location objects using the methodology discussed

previously. Next, the applet draws the title of the page (retrieved from

document.title

) and the URL

of the page (from

location.href

) onto the applet canvas.

Lastly, the

window

’s

eval()

method is used to evaluate a call to

getMessageFromApplet()

, which is a

JavaScript function that must be defined in the HTML page containing the applet. If the function doesn’t

exist when the applet is initialized, then a

JSException

occurs.

When including an applet that uses the LiveConnect package, you must set a special parameter to allow

it access to the HTML document. The parameter ’s name is

mayscript

, and it should be set to

true

width=”100” height=”100” id=”ExampleApplet”>

</object>

If you are using the old

element, then just include

mayscript

as an attribute:

<applet code=”ExampleApplet3.class” mayscript=”mayscript”

width=”100” height=”100” name=”ExampleApplet”>

</applet>

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