Details are server dependent, so consult your server admin or documentation. Other browsers correctly heed the server-provided MIME types, so they will reveal server misconfigurations. You can't, because the Web doesn't work that way. The server should be configured to identify a document's media type properly, as described in the answer to the previous question . The browser then decides what to do with it.
Different browsers are able to and configured to display different types of documents themselves.
Browsers are usually configured to handle other file types by using helper applications or by offering to save the file. There is no way for a web author to override the way the browser is configured to handle any given type of file. You can't, because the Web doesn't work that way. There is no way for a web author to override the way the browser is configured to handle any given type of file. Most browsers allow the user to download to disk if they want to.