Dynamic Web page
Dynamic Web pages can be defined as: (1)
Web pages containing dynamic content (e.g., images, text, form fields, etc.) that can change/move without the Web page being reloaded or (2)
Web pages that are produced on-the-fly by server-side programs, frequently based on parameters in the
URL or from an HTML form.
Web pages that adhere to the first definition are often called
Dynamic HTML or
DHTML pages.
Client-side languages like
JavaScript are frequently used to produce these types of dynamic Web pages.
Web pages that adhere to the second definition are often created with the help of
server-side languages such as
PHP,
Perl,
ASP/
.NET,
JSP, and languages. These server-side languages typically use the
Common Gateway Interface (CGI) to produce dynamic Web pages.
The word
dynamic is used in opposite to
static; see
Static Web page.
Client-side dynamic content is generated on the client's computer. The Web server retrieves the page and sends it as is. The Web browser then processes the code embedded in the page (normally
JavaScript) and displays the page to the user.
The innerHTML property (or write command) can illustrate the "Client-side dynamic page" generation: 2 distinct pages, A and B, can be regenerated (by an "event response dynamic") as
document.innerHTML = A and
document.innerHTML = B; or "on load dynamic" by
document.write(A) and
document.write(B).
The problems with client-side dynamic pages are:
* Some
browsers do not support the language or they do not support all aspects (like write command and innerHTML property) and of the language.
* The information cannot be stored anywhere but the user's computer, so it cannot really be used for
statistics gathering.
* Search engines are not able to run client-side languages and cannot crawl links generated by them.
* Some users have scripting languages disabled in their browsers due to possible security threats.
Ajax is a newer web development technique for creating client-side dynamic Web pages.
Google Maps is an example of a
web application that uses Ajax techniques.
Server-side dynamic content is a little bit more complicated.
# The browser sends an
HTTP request.# The server retrieves the requested
script or program.# The server executes the script or program which typically outputs an HTML Web page. The program usually obtains input from the
query string or
standard input which may have been obtained from a submitted Web form.# The server sends the HTML output to the client's
browser.
Server-side has many possibilities for dynamic content, but the use of it can be a strain on low-end, high-traffic, machines. Some Web sites use the
Robots Exclusion Standard to keep
Web crawlers from accessing dynamic pages for this reason. If not properly secured, server-side scripts could be exploited to gain access to a machine.
"Virtual documents" are Web documents for which the content, nodes or links, or all three, are created as needed.[
1]
It would appear that
Wikipedia may have addressed some of the
research issues raised by virtual documents
(in the contexts of digital libraries / information retrieval (?) ).*
Deep Web*
Common Gateway Interface
