The main goal of the HDF browser plug-in is click-and-view HDF files remotely and locally from popular web browsers. Different options of how to implement the plug-in will be presented for comments.

1. HDF Web-Browser Plug-in
Peter Cao, National Center for Supercomputing Applications
This work is supported in part by a Cooperative Agreement
with the National Aeronautics and Space Agency (NASA) and
National Center for Supercomputing Applications (NCSA)
HDF and HDF-EOS
Workshop VIII, October 2628, 2004
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2. Outline
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Plug-in Basics
Development issues
An example: windows plug-in for IE5
HDF and HDF-EOS
Workshop VIII, October 2628, 2004
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3. What Is HDFView
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A browser plug-in is a software program that extends
the power of Web browser by adding more features
and supporting more types of content than what the
standard browser provides
An HDF browser Plug-in is a windowed Plug-in that is
launched from Web browser to display HDF4 and
HDF5 files
Web Browser
New Datatype
Plug-ins
New Feature
HDF and HDF-EOS
Workshop VIII, October 2628, 2004
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4. Reasons for a HDF Plug-in
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Click-and-view: by clicking on or drag-drop a HDF file,
the browser will recognize and display the file (much like the
acrobat reader plug-in for pdf files)
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Easy install and update: downloading and installing
the plug-in is just a simple click. No uninstall and reinstall is
necessary for new release. Users will be asked for automatic
update when a new version is released
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Browse remote files: with predefined the MIME type,
the plug-in will take the advantage of the web browser to
browse HDF files over the internet
HDF and HDF-EOS
Workshop VIII, October 2628, 2004
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5. How Plug-ins Works
A standard set of plug-in APIs are defined for
communication between applications and the browser
 Netscape Plug-in APIs
 Microsoft ActiveX controls
Web Browser:
Internet Explorer
Netscape
Mozilla
Browser Side
Plug-in API
Plug-in
Java
C
C++
Plug-in Side
Plug-in API
HDF
Library
HDF File
HDF and HDF-EOS
Workshop VIII, October 2628, 2004
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6. Implementation Challenge
Plug-ins are platform and browser dependent
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Platforms
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Windows
Mac
Linux
Solaris
Browsers
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Internet Explorer
Netscape or Mozilla
HDF and HDF-EOS
Workshop VIII, October 2628, 2004
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7. Implementation Challenge
continue
Since Microsoft has removed support for Netscape plug-ins
from IE 5.5 SP 2 and beyond, plug-ins developed in Netscape
Plug-in APIs will not work on IE. Netscape/Mozilla does not
support ActiveX controls
NS Plug-in APIs
Microsoft ActiveX
Netscape/Mozilla
IE 5.5 SP 2 +
HDF and HDF-EOS
Workshop VIII, October 2628, 2004
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8. Choice: Microsoft ActiveX
Pros:
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Better performance (speed and memory)
Easy installation (one piece software)
Works best for IE, which has 80% of the users
Cons:
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Works only on IE and Windows.
Maintenance and support
HDF and HDF-EOS
Workshop VIII, October 2628, 2004
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9. Choice: Java Pluglet API
A Pluglet is a Plug-in that is written in Java and a close
1:1 implementation of the C++ Plug-in API in Mozilla
Pluglet
Pluglet Engine
(Java)
JVM
Pluglet Engine
(C++)
Plug-in API
(NS API)
Mozilla
ActiveX
IE
HDF and HDF-EOS
Workshop VIII, October 2628, 2004
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10. Choice: Java Pluglet API
continue
Pros:
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Support all major platforms
Easy maintenance (reuse HDFView code)
Cons:
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Lower performance (Java  C)
Requires Java Runtime Environment
Installation (classpath, JNI path, security)
HDF and HDF-EOS
Workshop VIII, October 2628, 2004
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11. Short Demo: Plug-in For IE
HDF and HDF-EOS
Workshop VIII, October 2628, 2004
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12. Questions
HDF and HDF-EOS
Workshop VIII, October 2628, 2004
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