End-User Programming for the Web
Michael Bolin & Robert Miller
Motivation
On the desktop, an application can expect to control its user
interface down to the last pixel, but on the World Wide Web, a content
provider has no control over how the client will view the page, once
delivered to the browser. This creates an opportunity for end-users
who want to automate and customize their web experiences, but the
growing complexity of web pages and standards prevents most users from
realizing this opportunity.
Approach
Chickenfoot is a
scripting environment embedded in the Firefox web browser that enables
end-user programmers to customize and automate their interaction with
the web by talking about objects they see in a web page.
Most approaches to web automation and screen scraping require the
programmer to understand the underlying structure of the web page
because they require the user to write syntactic patterns, such as
regular expressions or XPATH, in order to identify elements in a web
site. Chickenfoot scripts differ because they support the use of
semantic patterns, so the user never needs to view the raw HTML of the
web page. For example, the name of the HTML element for Yahoo!'s
search box is "p," so other automation systems may let the user
programmatically set the contents of the search box by writing
something like the following:
html.body.p[3].table.tr[2].input.p = "search terms"
whereas in Chickenfoot, an end-user programmer could write:
enter('search box', 'search terms')
The former is tedious to write because it requires the author to plumb
through several hundred lines of machine-generated HTML to find the
name for
the textbox. Further, this script will fail if Yahoo! decides to change
the
textbox's name or its location in the page.
By contrast, the Chickenfoot code is easier for an end-user programmer
to
write and maintain because he simply needs to view the web page to
write the
script. Additionally, Chickenfoot scripts are more robust to changes in
the
web site.
With Chickenfoot, users can automate web tasks, programmatically
extract
content from web sites, and customize how web pages are presented in
their
browser.
Some examples of tasks we have accomplished with Chickenfoot scripts
are:
- Highlighting SAT vocabulary words in a web page.
- Hyperlinking Java types in sample Java code to their Javadoc API.
- Enabling users to sort HTML tables by clicking on a column header.
- Concatenating multipage pages of search results into one page.
- Converting web pages into black-and-white so they are easier to
read.
- Appending icons after hyperlinks that reflect the file type of
the target of the link.
Acknowledgements
This work was supported in part by the National Science Foundation
under award number IIS-0447800. Any opinions, findings, conclusions or
recommendations expressed in this publication are those of the authors
and do not necessarily reflect the views of the National Science
Foundation.
References:
[1] Michael Bolin, Matthew Webber, Philip Rha, Tom Wilson, and
Robert C. Miller. "Automation
and Customization of Rendered Web Pages." UIST
2005, pp. 163-172.
Winner of best paper award. [Powerpoint slides]
[2] Michael Bolin. End-user
Programming for the Web. MEng thesis, Massachusetts Institute
of Technology, June 2005. Winner of William A. Martin Memorial
Thesis Prize for an outstanding Master's thesis in computer science.
[3] Michael Bolin and Rob Miller. "Naming
Page Elements in End-User Web Automation." Workshop on End-User
Software Engineering, ICSE 2005.
