[What are they?] - [Using captive
search with LII collections] - [LII helpers for other
collections] - [Rolling your own]
NB: This document, like others in the "building blocks"
series, assumes as part of its design that you will make frequent
use of the "view source" feature in your browser to see how things have
What are captive searches?
Captive or embedded searches are a useful species of hyperlink
in situations where you need to retrieve a range of resources (say, a number
of judicial opinions on a common topic) or where the body of material from
which you want to retrieve is expected to change over time -- in other
words, in those situations where a dynamic search retrieving a list of
documents is more useful than a static link to a single case or document.
The idea is to construct an ordinary link which, when clicked on, permits
the student or user to launch a predetermined search of some body of material.
Here's an example which gets recent
Supreme Court cases related to bankruptcy.
For example, a law teacher constructing a Web page for a constitutional
law course might well want to point to all
recent cases of the US Supreme Court where the term "civil rights" appears
in the syllabus -- and would also want to be certain that any new cases
decided by the court will be captured as they are added to the corpus.
We use this technique often in the construction of our
topical pages, where we need links which will capture (say) every bankruptcy
decision of the New York Court of Appeals, and continue to do so even
as our collection grows.
You can puzzle out how to construct such a link for
almost any searchable collection of data; some collections are easier than
others. A few providers like the LII have constructed interfaces
and engines to make this task easier..
LII services, collections, and helpers
The LII provides you with two kinds of help in constructing captive searches.
Our own collections are designed to make it easy to build links which reach
into our search engines. We have also designed software "helpers"
to make construction of captive searches for some non-LII collections (such
as the CFR at the House of Representatives Law Library) easier for you
In no particular order, here are instructions for several important
collections here and elsewhere. If your favorite isn't in the list, we
provide help for you in rolling your own captive search.
LII collections and services:
Decisions of the US Supreme
Court, current and historic, at the LII and elsewhere
Decisions of the New York
Court of Appeals
LII Topical Pages
The United States Code
The Uniform Commercial Code
The Federal Rules of Evidence.
The Federal Rules of Civil Procedure
US Administrative Procedure Act
Introduction to Basic Legal Citation
Civil Rights statutes of the United States
US Copyright Act, Berne Convention, and selected cases
US Patent Act and selected cases
Lanham Act and selected cases
Legal Ethics materials
Securities Act of 1933
Securities Exchange Act of 1934
Helpers for non-LII collections
Decisions of the US Supreme Court (multiple sources)
Code of Federal Regulations (House of Representatives)
Decisions of the US Circuit Courts of Appeal (multiple providers)
Geek Techneek: rolling your own
Figuring out how to make your own captive searches on a new collection
isn't all that difficult. Most of the time, it's a matter of looking
at whatever form the collection uses to enter search terms, and moving
the information into appropriate syntax. Here's
a simple example, similar to what we might see if we selected View/Page
source while looking at the search screen for a caselaw collection:
<!-- Form for querying
a caselaw collection in the Western District of East Central Anywhere -->
Enter your search terms:<BR>
The trick, of course, is to build a static URL which incorporates all
the information which a browser would send to the search engine if the
user had filled in the form and pressed the 'submit' button. This
is actually pretty easy to do, if you know the format in which the browser
is supposed to submit the information. The URL for an entire query
should consist of :
So in our example, a captive link to search on the term 'bankruptcy' would
look like this:
the URL appearing in the "ACTION" attribute of the FORM tag , followed
a question mark, followed by
"name=value" pairs representing the values of all the fields (straightforward
in our example but a little trickier when you start dealing with things
like radio buttons, SELECT lists, and checkboxes), separated by ampersands
My captive query.
Fine points involving search terms
Note that values are not quoted (in other words, you don't say
The astute reader is doubtless thinking that there has to be some special
syntax for indicating multiple terms, and the astute reader is, of
course, right. To capture a search for "civil rights", you'd say user_query=civil+rights
. Other problems are presented by nonalphabetic characters
in search strings -- even things like parentheses and forward slashes,
which show up pretty commonly with search engines which support booleans
and proximities. These get encoded with hexadecimal escapes (aren't
you glad you have that ASCII table handy?). The sort-of-Lexis-ish
w/2 guns) and money
To be perfectly honest, I'm not sure exactly when you'd use a %20 escape
to replace a space, and when you'd use the + character; the above represents
a guess. It may well vary by search engine, and some experimentation
is in order.
Hijacking more sophisticated forms
The preceding examples show how simple it is to "take over" forms which
only use simple INPUT tags and build captive URLs from them Other
kinds of fields are a little harder to deal with, but not much. For
a group of radio buttons, you send the name of the group plus the value
of the button which is checked, eg. radiogroup=my_value.
For a checkbox, send nothing if the checkbox isn't checked;
send the value "on" if it is, eg. checked_checkbox=on.
For SELECT fields, send the name of the SELECT field and the value of the
option to be selected, eg:
<OPTION value="1"> One
<OPTION value="2"> Two
would yield my_select=1
if we were trying to force the first option.
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