This article describes the settings that are available in the Applications panel of the Firefox OptionsPreferences window.
The Applications panel allows you to choose how Firefox handles different types of files. For each content type Firefox recognizes, you may select an action that Firefox will use to handle that type of content. You can view the file content in the Firefox window with Firefox for natively supported formats (Podcast, Web Feed, PDF)) or with a plugin, open the file with an application installed on your computer (or in some cases, with a web application), or you can save the file to your downloads folder.
To change how Firefox handles a file type in the list, click on its name to select it. Open the drop-down menu to select the download action you want Firefox to use:
Some file formats may have multiple content types, also called Internet media types, (for instance, audio/wav and audio/x-wav for Wave Sound) that you will need to change. Also, when a plugin is available to handle a content type and you choose a different action for that type, Firefox will only take your chosen action when you access the type directly. For example, you may choose to open these files with a media player application instead of using the plugin that is set to open it. In such cases, your chosen application will be used for file downloads but, when the content type is embedded inside a web page, Firefox will continue to use the plugin to handle the content type.
The Applications panel has limited functionality for editing. You can change the action for an existing file type but you cannot add or remove file types. Entries are added automatically when you download files and select actions for them. See Adding download actions.