Page 296 - DCAP408_WEB_PROGRAMMING

Web Programming

Notes services such as America on-line also provide an E-Mail system for their customers. When
choosing your E-Mail package, you may want to keep the following in mind:

 Is the E-Mail client’s interface user friendly?
 Does the E-Mail package have an electronic phone book, where you can keep a list of your
important E-Mail addresses?

 Does the E-Mail package have the ability to encode and decode files attached to E-Mail
messages?
 Does the E-Mail package have a spelling checker?
While all the items listed previously are not vital to make an E-Mail package usable, they are
features that many E-Mail packages offers as a matter of course.
If your ISP has a Post Office Protocol (POP) server, you have a wide choice of E-Mail applications.
You cannot use most E-Mail programs to get your E-Mail if you use AOL; instead, you use AOL’s
own program or its Web site. Before you can receive E-Mail, your ISP must know who you are,
your client application must be set up, if someone needs to send you E-Mail.
Self Assessment

Fill in the blanks:
12. Windows comes with its own E-Mail client called ……………………
13. E-Mail programs tend to work alike, even down to the keystrokes required to execute a
……………………

13.5 Caching

Many visitors access the internet through a proxy. The visitors submit their request through
their browser and the request is then sent to a proxy, which serves as a funnel for many
computers making requests to the internet. One of the things proxy does is to store a cache of
pages requested by all the users of the proxy. So instead of retrieving the same page many
times form the internet, the proxy merely returns the cached page to the person making the
request.
The cache control property is your way of instructing the proxy to cache or not to cache. The code
must precede any HTML and take the following form:

Response.CacheControl= “public”
Or
Response.CacheControl= “private”
By default, the property is to private, which indicates that the content should not be buffered. If
you do want the text of you ASP buffered, simply set the property to Private.
HTML pages and graphics can be stored in the cache. Response has two properties that can be
used to determine how long an ASP page be cached.
These two properties are:
Response.Expires and
Response.ExpiresAbsolute

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