Question

I read that you could call JavaScript code from a Java Applet by calling

JApplet.getAppletContext().showDocument( 'javascript:alert('Hello World');' ); 

However, when I do this i get the following error:

java.net.MalformedURLException: unknown protocol: javascript 

How do I work around this?

Answer 1

I get the same exception as you do because of that the URL class does not accept javascript: as a valid protocol.

There is a workaround though; supply an URLStreamHandler to the URL constructor.

Example:

final URLStreamHandler streamHandler = new URLStreamHandler() {      @Override     protected URLConnection openConnection(URL u)         throws IOException {         return null;     }  };  try {     getAppletContext().showDocument(         new URL(null, 'javascript:alert('It works!');', streamHandler)); } catch (MalformedURLException me) {     //log or whatever }