window.opener is changed during redirect from Applet in Java 1.7.0_04-b20 but not in 1.7.0_03-b5

[Sascha Kaestle]

Hello everyone


I ran into an issue with the javascript property `window.opener` (which keeps a reference to the window that opened the popup) in conjunction with a redirect from within an applet. Whenever a redirect happens from within the applet, `window.opener` was changed to the current pop-up. Even stranger is the fact that this change was introduced with a recent java update quite recently: this did not happen with `java 1.7.0_03-b05` but started happening with `java 1.7.0_04-b20`. Now this might be some exotic usecase but still, I'm wondering if this change was intentional.

To get to the bottom of this I have written a small test to demonstrate the behavior in question. The HTML-Sites can be found here: http://files.newsnetz.ch/applet_test. It does only work in Firefox (which is OK for my usecase)



1. The `index.html` page contains the following javascript:

window.name = "index.html";
	
        function open_new_window() {
            window.open('applet.html', 'applet.html', 'width=1050,height=680,scrollbars=yes,status=yes').focus();
            return false;
        }

I set the windows name to "index.html" (for identification purpose) and provide a function that will open applet.html in a popup-window.
It also contains a link which calls this function:

<a href="#" onclick="open_new_window(); return false;">open applet.html in new                
        window</a>

2. after clicking the link, `applet.html` is opened in a popup. This contains the following javascript:

window.name = "HelloWorldApplet.html";
		
        alert("opener is now: "+window.opener.name);
		
        function on_load() {
            alert("changing bgcolor of opener to red");
            window.opener.document.body.style.background='red';
        }

I set this popup's window.name to "applet.html" (for identification purpose) and alert the current `window.opener.name`. When the body fires the onload event, I change the openers background color to red.

Also, this page contains an applet, which has a button that will fire a redirect to `redirect.html`

        import java.applet.Applet;
        import java.awt.Button;
        import java.awt.FlowLayout;
        import java.awt.event.ActionEvent;
        import java.awt.event.ActionListener;
        import java.net.MalformedURLException;
        import java.net.URL;
        import java.util.logging.Level;
        import java.util.logging.Logger;

        public class HelloWorldApplet extends Applet implements ActionListener {

            Button redirectButton;
    
            @Override
            public void init() {
                super.init();
        
                setLayout(new FlowLayout());
                redirectButton = new Button("Redirect now!");
                add(redirectButton);
        
                redirectButton.addActionListener(this);
            }

            @Override
            public void actionPerformed(ActionEvent ae) {
                try {
                    this.getAppletContext().showDocument(new URL(this.getDocumentBase(), "redirect.html"), "_self");
                } catch (MalformedURLException ex) {
                    Logger.getLogger(HelloWorldApplet.class.getName()).log(Level.SEVERE, null, ex);
                }
            }
        }

3. after clicking the button in the applet, `redirect.html` is opened in the same popup-window. This page contains the following javascript:

window.name = "redirect.html";
		
        alert("opener is now: "+window.opener.name);
        function on_load() {
            alert("changing bgcolor of opener to green");
            window.opener.document.body.style.background='green';
        }

I set this popup's window.name to "redirect.html" (for identification purpose) and alert the current `window.opener.name`. When the body fires the onload event, I change the openers background color to green.


With `java 1.7.0_03-b5` the following happens:

1. After clicking the link in `index.html`, `applet.html` is opened in a popup window. The alert shows `index.html` as being the openers name. Then the backgroundcolor of the opener is changed to red
2. After clicking the button in the applet `redirect.html` is opened in the same window. The alert shows `index.html`as being the openers name. Then the backgroundcolor of the opener is changed to green

so far so good... but with `java 1.7.0_04-b20` the following happens:

1. After clicking the link in `index.html`, `applet.html` is opened in a popup window. The alert shows `index.html` as being the openers name. Then the backgroundcolor of the opener is changed to red
2. After clicking the button in the applet `redirect.html` is opened in the same window. The alert shows 'redirect.html` as being the openersname. Then the backgroundcolor of the opener (which is the popup-window now!) is changed to green.

So it seems the redirect issued by the Applet via `this.getAppletContext().showDocument(new URL(this.getDocumentBase(), "redirect.html"), "_self");` changes the window.opener property to the window it changed the URL in...

I would appreciate any insights into why this behavior might have changed or if you could imagine a workaround to this problem.

Thanks a lot for your time