Error when calling javascript method from applet

Question

I am trying to call javascript method from an Applet using netscapte.java.JSObject.

in the applet:

JSObject window = JSObject.getWindow(this.Class); 
Object[] args = ....  //arguments 
window.call("javascriptMethodName", args);

But I get the exception at window.call:

JavaScript error while calling "callFromJava"
netscape.javascript.JSException: JavaScript error while calling "callFromJava"
    at sun.plugin2.main.client.MessagePassingJSObject.newJSException(Unknown Source)
    at sun.plugin2.main.client.MessagePassingJSObject.waitForReply(Unknown Source)
    at sun.plugin2.main.client.MessagePassingJSObject.call(Unknown Source)
    at TextBoxApplet.jButton1_actionPerformed(TextBoxApplet.java:57)
    at TextBoxApplet.access$000(TextBoxApplet.java:16)
    at TextBoxApplet$1.actionPerformed(TextBoxApplet.java:36)
    at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
    at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
    at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
    at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
    at java.awt.Component.processMouseEvent(Unknown Source)
    at javax.swing.JComponent.processMouseEvent(Unknown Source)
    at java.awt.Component.processEvent(Unknown Source)
    at java.awt.Container.processEvent(Unknown Source)
    at java.awt.Component.dispatchEventImpl(Unknown Source)
    at java.awt.Container.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
    at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
    at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
    at java.awt.Container.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.EventQueue.dispatchEvent(Unknown Source)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.run(Unknown Source)

The JSObject is NOT null. Have anyone encountered this ? Thanks a lot.

I don't know the answer, but my guess would be that "JavaScript error" implies that it's an error in the JavaScript code. Could you post that? — Sasha Chedygov
guess you right. I thought it is an bug and wanna see if any one fix it. <code> function callFromJava(comId) { var textBox = document.getElementById(comId); textBox.setValue("Triggered By Applet"); } </code> I am trying to get the af:inputText by its id. — Khue Vu
What kind of an element is "textBox"? If it's an <input> or <textarea>, try setting the content with textBox.value("Triggered By Applet"); By default, they don't have a "setValue" method. — Lauri Lehtinen
It is an af:inputText. I am wrong on this as I treated it like html component. — Khue Vu
As in adf, I need to use AdfPage.page.findComponentByAbsoluteId("") instead. — Khue Vu

Lauri Lehtinen Lauri Lehtinen · Accepted Answer · 2010-06-17T23:39:35

I did a quick test and my findings correlate well with musicfreak's comment.

With the following Applet:

public class MyClass extends JApplet {
    public void init() {
        JSObject window = JSObject.getWindow(this); 
        Object[] args = new String[] { "bar" }; 
        window.call("foo", args); 
    }
}

and the following markup (notice the erroneous JavaScript - there's no baz method in the bar argument I'm passing):

<html>
  <head>
    <title>MyAppletTest</title>
  </head>
  <body>
    <script type="text/javascript">
      function foo(bar) { bar.baz(); }
    </script>
    <applet code="MyApplet.class"></applet>
  </body>
</html>

I get the error:

netscape.javascript.JSException: JavaScript error while calling "foo"
    at sun.plugin2.main.client.MessagePassingJSObject.newJSException(Unknown Source)
    at sun.plugin2.main.client.MessagePassingJSObject.waitForReply(Unknown Source)
    at sun.plugin2.main.client.MessagePassingJSObject.call(Unknown Source)
    at MyApplet.init(MyApplet.java:13)

If I fix my JavaScript function by replacing bar.baz() with alert(bar) for example, everything works fine.

Long story short - take another look at the JavaScript function you are trying to call, as well as the parameters your Applet passes with the call.

Error when calling javascript method from applet

2 Answers