Javascript to Java Applet communication

Question

I am trying to pass a selected value from HTML drop-down to an Applet method, using setter method in the Applet. But every time the Javascript is invoked it shows "object doesn't support this property or method" as an exception.

My javascript code :

function showSelected(value){
    alert("the value given from"+value);
    var diseasename=value;
    alert(diseasename);
    document.decisiontreeapplet.setDieasename(diseasename);

    alert("i am after value set ");
}

My applet code :

package com.vaannila.utility;


import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;

import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;


import prefuse.util.ui.JPrefuseApplet;

public class dynamicTreeApplet extends JPrefuseApplet {

    private static final long serialVersionUID = 1L;
    public static int i = 1;
    public String dieasenameencode;
    //System.out.println("asjdjkhcd"+dieasenameencode);
    public void init() {
        System.out.println("asjdjkhcd"+dieasenameencode);
        System.out.println("the value of i is " + i);
        URL url = null;
        //String ashu=this.getParameter("dieasenmae");
        //System.out.println("the value of the dieases is "+ashu);

        //Here dieasesname is important to make the page refresh happen 

        //String dencode = dieasenameencode.trim();
        try {
            //String dieasename = URLEncoder.encode(dencode, "UTF-8");
            // i want this piece of the code to be called 
            url = new URL("http://localhost:8080/docRuleToolProtocol/appletRefreshAction.do?dieasename="+dieasenameencode);
            URLConnection con = url.openConnection();
            con.setDoOutput(true);
            con.setDoInput(true);
            con.setUseCaches(false);
            InputStream ois = con.getInputStream();
            this.setContentPane(dynamicView.demo(ois, "name"));
            ois.close();

        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (FileNotFoundException f) {
            f.printStackTrace();

        } catch (IOException io) {
            io.printStackTrace();
        }
        ++i;
    }

    public void setDieasename(String message){
        System.out.println("atleast i am here and call is made ");
        this.dieasenameencode=message;
        System.out.println("the final value of the dieasenmae"+dieasenameencode);

    }

}

My appletdeployment code :

<applet id="decisiontreeapplet" code="com.vaannila.utility.dynamicTreeApplet.class" archive="./appletjars/dynamictree.jar, ./appletjars/prefuse.jar" width ="1000" height="500" >    
</applet>

possible duplicate of [value passing in java applet](http://stackoverflow.com/questions/7269466/value-passing-in-java-applet) — Nate, Sep 02 '11 at 02:22
@Nate That does look very familiar! OP please don't repost questions. — Andrew Thompson, Sep 02 '11 at 04:57

score 7 · Accepted Answer · answered Sep 02 '11 at 02:44

Change..

document.decisiontreeapplet

..to..

document.getElementById('decisiontreeapplet')

..and it will most likely work.

E.G.

HTML

<html>
<body>
<script type='text/javascript'>
function callApplet() {
    msg = document.getElementById('input').value;
    applet = document.getElementById('output');
    applet.setMessage(msg);
}
</script>
<input id='input' type='text' size=20 onchange='callApplet()'>
<br>
<applet
    id='output'
    code='CallApplet'
    width=120
    height=20>
</applet>
</body>
</html>

Java

import javax.swing.*;

public class CallApplet extends JApplet {

    JTextField output;

    public void init() {
        output = new JTextField(20);
        add(output);
        validate();
    }

    public void setMessage(String message) {
        output.setText(message);
    }
}

Please also consider posting a short complete example next time. Note that the number of lines in the two sources shown above, is shorter that your e.g. applet, and it took me longer to prepare the source so I could check my answer.

hi andrew its not working even now everytime i try to invoke setmethod in my applet object its saying object doesnot support this method ..is their any way to debug this . — bhalkian, Sep 02 '11 at 05:48
*"its not working"* The example shown above works for me in FF. *"is their any way to debug this(?)"* If using FF, open the Error Console (Ctrl+Shift+J). — Andrew Thompson, Sep 02 '11 at 06:04
was a cache problem .it worked for me as well :) thanks a ton — bhalkian, Sep 02 '11 at 06:06

score 1 · Answer 2 · answered Sep 02 '11 at 02:26

1

Try changing the id parameter in your applet tag to name instead.

<applet name="decisiontreeapplet" ...>
</applet>

answered Sep 02 '11 at 02:26

Perception

79,279
19
185
195

score -1 · Answer 3 · answered Sep 02 '11 at 02:18

-1

Try passing parameters using the param tag:

http://download.oracle.com/javase/tutorial/deployment/applet/param.html

answered Sep 02 '11 at 02:18

Daniel Pereira

1,785
12
10

score -1 · Answer 4 · answered Oct 12 '11 at 12:49

I think the <applet> tag is obsolete and <object> tag shoudl be used instead. I recall there was some boolean param named scriptable in the object tag.

Why you do not use deployment toolkit ? It would save you a lot of trying - see http://rostislav-matl.blogspot.com/2011/10/java-applets-building-with-maven.html for more info.

Javascript to Java Applet communication

4 Answers4

E.G.

HTML

Java

Linked