July 2009
Beginner to intermediate
384 pages
12h 56m
English
Content preview from Beautiful Data
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Chapter 9. Surfacing the Deep Web
What Is the Deep Web?
THE TERM "DEEP WEB" REFERS TO WEB CONTENT THAT LIES HIDDEN BEHIND HTML FORMS. IN ORDER to get to such content, a user has to perform a form submission with valid input values. Take, for example, the store locator form in Figure 9-1. Searching for stores in the zip code 94043 results in a web page with a listing of stores. The result page is an example of a web page in the Deep Web.
Figure 9-1. The Borders Store Locator form and a deep-web page resulting from a particular form submission. (See Color Plate 21.)
The Deep Web has been acknowledged as a significant gap in the coverage of search engines. This is because search engines employ web crawlers to discover web pages that will be included in their index, and traditionally these web crawlers were believed to rely exclusively on hyperlinks between web pages to discover new web content. They lacked the ability to automatically perform form submissions, and hence web pages behind forms were not included in the index of a search engine. The web page with the form typically carries very little information about the content of the pages behind the form; thus, common web users could get to Deep Web content only if they already knew of the existence of the corresponding HTML form or if search engines somehow led them to the form. They then had to perform the ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.