RR_03_02

Assuming Accurate Layout Information is Available: How do we Interpret the
Content Flow in HTML Documents?
Abstract
Accessing multi-modal HTML documents. such as web
pages. by devices of lower form factor is a growing
practice. There are three problems of using a small
handheld device for accessing web pages. the display area
is small. the network speed is low. and the device
capability is lower. Often the devices are unable to run IE
or other browsers. and when they can. the browsers have
lower levels of jimctionality. A direct consequence is that
web pages written f or desktop devices with HTML 4 with
Cascading Style Sheets (CSS). image maps. and flash
multi-media plug-ins are often not viewable in these
smaller devices. In order to solve this problem.
researchers have been using techniques such as
transcoding and re-authoring to re-format web pages and
re-jlowing them to the small devices. Some of these
techniques use secondary information about the HTML
data structure and content association in terms of
semantics of the web pages. but none has access to
accurate layout information before it is rendered.
Assuming we do have access to this type of information.
we can take a whole new perspective to this web page reauthoring
problem. This paper discusses some ideas about
the possible use of accurate layout information while
automatically re-authoring web pages.
1. Introduction
Web pages written in HTML do not provide adequate
information about the final layout. This is only known
when the page is rendered using one of the standard web
page browsers such as IE®, Netscape® or Opera®. This is
so as many of the elements in the web pages are dynami c.
For example, the width of a column may vary based on the
browser window size. This makes calculating accurate
layout information very difficult. But what if we did have
access to this information? How do we use this to improve
web page re-authoring? This paper di scusses some ideas
about how we can exploit this information to produce
Hassan Alam and Fuad Rahman§
BeL Technologies Inc.
fuad@bcltechnologies. com
better re-flow of web pages targeted to small handheld
devices.
2. Related Work
There is a growing demand for viewing web pages on
small screen devices. Mobile viewing allows keeping in
touch with the rest of the world while on the move. So
web page re-authoring can be of great interest. Another
motivation is to summarize web content to help in rapid
viewing, as time is a very important commodity and the
amount of information available these days makes it
impossible to browse through entire web sites [I]. Often
there is a demand for alternative browsing, such as the use
of voice [2, 3]. Most email browsing software now support
HTML pages, which make the problem of universal email
accessibility a problem of web page manipulation. Last,
but not the least, web page manipulation is often required
in order to extract content and transfer it to other formats,
such as PDF and others. In this scenario, web page
manipulation supported with document analysis
techniques is the best choice.
Before we start, here is a very brief outline of past
work. Over the years, researchers have proposed different
solutions to the problem of web page re-authoring. The
possible solutions can be categorized as:
• By Hand: Manipulate web sites by hand.
• Transcoding: Automatically replace tags with
device and target specific tags. In this case, the
content flow is identical to the flow in the HTML
data structure [4].
• Re-authoring: Automatically capture the structure
and intelligently re-flow content in a different flow
other than in the original document. There are
many vari ations of this approach:
• Table of Content (TOC): the document is
re-created based on extracted content and
a heading is created. This heading hides a
hyperlink, which if selected, can load up
details associated with the headline [5].
l Corresponding author. The authors gratefu lly acknowledge the support of a Sma ll Business Innovation Research (SBIR) award under the supervision
of US Army Communica tions-Electronics Command (CECO M).
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