Creating an Applet from an Application

Question

So i'm developing my own version of the '80s Space Invader game for class, and one of the requirments is that we have to turn in an application, but also post an Applet version on a website. The game is pretty much done, but I am having trouble creating the Applet from the Application. I've done most of the stuff that i thought you were supposed to do. The thing is, it will run whenever i use the appletviewer from the dos prompt just like it does when i'm running the application. However, when Ii try to view it in an actuall explorer window, it wont load.
The way the program was designed, it had a "SpaceInvaders" class that had the main method, which only had about 4 lines. Then i had a DrawFrame class that extended JFrame, and that had the bulk of the code in it. The main method of the SpaceInvaders class had a "DrawFrame frame = new DrawFrame();" statement, and then a couple set.whatever statements. to change it to an applet, i just commented out the whole of the SpaceInvaders class, then i renamed the DrawFrame class to "public class SpaceInvaders extends JApplet" changed the consructor to the "init()" method, and commented out the setSize and setTitle statements, and also i imported java.applet.*;
when i try to run the html file in firefox, all i get is the frame with a little red 'X' in it, and at the bottom it says "Applet SpaceInvaders notinited"
any help, ideas, or tips would be greately appreciated. Thanks in advance, and if you need any more info, let me know.

Answer 1

i created a very simple applet:
import java.applet.*;
import java.awt.*;
* The HelloWorld class implements an applet that
* simply displays "Hello World!".
public class HelloWorld extends Applet {
    public void paint(Graphics g) {
        // Display "Hello World!"
        g.drawString("Hello world!", 50, 25);
}and it ran just fine inside of a browser. I've also ran other applets that should be very similar to mine, but still mine doesn't work.