The Java Applet Properties dialog box changes Java applets properties.

It contains the following sections:

The Class File section. To select an applet class file from the Class File window, you must first import it into your web site project (click on the Import button, if you have not imported the needed files into the site yet).

A Java Applet can consist of more than one Class Files and resource files (JPEG, AU or other file formats). You must import all necessary files into your Web Site. Then you must insert a primary Class File into the web page and set its properties.

The Alignment section. To align a Java applet on the web page, check the Alignment check box. Then select a desired alignment style from the list of available styles:

The Parameters section. Use appropriate buttons to add or remove applet  parameters.

To change a name or a value, double click on it and enter a new name or value.

To change a parameters order, click on the Up or Down buttons.

The Alternate String section. Text entered in the Alternate String text box will be displayed instead of a Java applet if the applet cannot be displayed in a browser window for any reason.

The Size section. Sets the Horizontal and Vertical sizes of a Java applet.

The Spacing section. Adds space between a Java applet and other objects on the web page. To set spacing, check the Spacing check box and enter Horizontal and/or Vertical spacing values.

Click on the Extra HTML button to insert an additional HTML code into a current HTML tag.
You must be familiar with the HTML language to use this feature correctly.