www.webdeveloper.com
Page 1 of 2 12 LastLast
Results 1 to 15 of 22

Thread: Differnece of this cache ...

Hybrid View

  1. #1
    Join Date
    May 2003
    Posts
    7

    Exclamation Differnece of this cache ...

    Hi everyone,

    Would like to know what's the difference betwen these two statements:

    <META HTTP-EQUIV="Expires" CONTENT="-1">
    <META HTTP-EQUIV="Expires" CONTENT="0">

    What's the difference using between "-1" and "0".

    By the way, are there anyway to remove cache that store any script and images?

    Thanks.

  2. #2
    Join Date
    Dec 2002
    Location
    Calgary, Canada
    Posts
    2,653
    both statements are suppose to let the browser / web server know that a fresh copy of the web page is required.
    W3c stadnard does not define any values for the contents attribute,In my understanding value of the content is related to the webserver used.

  3. #3
    Join Date
    Nov 2002
    Location
    Baltimore, Maryland
    Posts
    12,270
    The HTTP-EQUIV META elements are supposed to allow web authors to tinker with the HTTP response header on some servers. Some browsers also pay attention to it, but we're really talking here about the HTTP specification. And both of those are illegal values. The header is supposed to employ a valid date of a particular format and relative values are not allowed. However, the specification does state that any illegal date is to be taken to have occured sometime in the past. Which is to say that those two statements are exactly he same.
    “The power of the Web is in its universality. Access by everyone regardless of disability is an essential aspect.”
    —Tim Berners-Lee, W3C Director and inventor of the World Wide Web

  4. #4
    Join Date
    May 2003
    Posts
    7
    I see. But seem like it's not working as i had put it into my code as below. It's for IE and Netscape.

    _____________________________________________________

    <html>
    <head>
    <title></title>
    <META HTTP-EQUIV="Pragma" CONTENT="no-cache">
    <META HTTP-EQUIV="Expires" CONTENT="-1">
    </head>
    <body onLoad="if ('Navigator' == navigator.appName) document.forms[0].reset();" bgcolor="#CCCCCC" leftmargin="0" topmargin="0" marginwidth="0" marginheight="0">

    The context for main page are here .......

    </body>
    <HEAD>
    <META HTTP-EQUIV="Pragma" CONTENT="no-cache">
    <META HTTP-EQUIV="Expires" CONTENT="-1">
    </HEAD>
    </html>

    _____________________________________________________

    Please help me ..... It's urgent. Thanks.

    Rgds.

  5. #5
    Join Date
    Dec 2002
    Location
    Calgary, Canada
    Posts
    2,653
    It doesn't make sense,but did you try to use 0 or left it empty without any thing in it?

  6. #6
    Join Date
    Nov 2002
    Location
    Baltimore, Maryland
    Posts
    12,270
    It's not supposed to work. At least not necessarily. It's what's in the HTTP header that matters and some servers use those meta tags to adjust the HTTP header.
    “The power of the Web is in its universality. Access by everyone regardless of disability is an essential aspect.”
    —Tim Berners-Lee, W3C Director and inventor of the World Wide Web

  7. #7
    Join Date
    May 2003
    Posts
    7
    Had tried with "0".
    So, you mean it should not?

    I found that in http://www.htmlgoodies.com/beyond/nocache.html

    Please advice. Thanks.

  8. #8
    Join Date
    Nov 2002
    Location
    Baltimore, Maryland
    Posts
    12,270
    HTML Goodies is a very, very bad site full of lots of incorrect and incomplete information. My advice is that you avoid it at all costs.
    “The power of the Web is in its universality. Access by everyone regardless of disability is an essential aspect.”
    —Tim Berners-Lee, W3C Director and inventor of the World Wide Web

  9. #9
    Join Date
    Dec 2002
    Location
    Calgary, Canada
    Posts
    2,653
    Its a tough call,It could be the web server is not reading this http value ata all,in that case whatever you do is waste,
    the typical value that http server should see is something like this

    Expires: Tue, May 2004 17:20:00 GMT//expiration date is given
    Expires: 0 //no cache intended
    Pragma: no-cache

    You might end up finding out that it was your webserver...So I kinda agree with charles that its one of those html things like "referer" where you are not completely independent.

  10. #10
    Join Date
    Feb 2003
    Location
    Wales, UK
    Posts
    3,148
    Originally posted by Charles
    HTML Goodies is a very, very bad site full of lots of incorrect and incomplete information. My advice is that you avoid it at all costs.
    [serious question]Are there any good sites out there in your opinion Charles? I regularly hear you shouting at sites, but never complimenting one![/serious question]

    dave
    In a world without walls and fences - who needs Windows and Gates?! - Unknown Author
    "And there's Bill Gates, the...most...famous...man in the...ah...Microsoft." -- A TV commentator for the 2000 Olympics.


    Web Design Faq? | W3C | Validator | Accessibility testing | Speed up your PC | Wura | Box Model Research

  11. #11
    Join Date
    Jan 2003
    Location
    Atlanta, GA
    Posts
    571
    I am not answering on behalf of Charles. Its my personal experience speaking.

    HTML goodies is nice for a beginer, as it starts simple and keeps things simple. But if you want to graduate to doing any serious web designing, HTML goodies leave a lot to be desired. I realized I had to unlearn a lot of things that I got from HTML goodies. I can't pinpoint at any right now, but I am sure there were a lot.

    One site I would definitely recommend is
    http://www.w3schools.com/

    If you do HTMLing to make your family photos available to your grandma, HTMLgoodies is the site for you. If you want to attract potential recruiters or if you are into anything more than a only-for-my-family site, you need to learn.

    I guess my dislike of HTMLgoodies stems from didn't-live-up-to-my-expectations syndrome. I have a page on my website that links to HTMLgoodies saying "This is the best site in the world". I actually thought that when I started HTMLing. And now that I understand things better than I did ca 3 years ago, I've begun to REALLY dislike HTMLgoodies.

    Still, the site doesn't qualify for axis-of-evil.

  12. #12
    Join Date
    Nov 2002
    Location
    Baltimore, Maryland
    Posts
    12,270
    I have found HTML Goodies to be particularly bad for beginners. It teaches a lot of stuff that is simply wrong and beginners are not going to know that it's wrong. If they ever get around to the next step they will have to unlearn everything.

    I'm afraid to say that I haven't seen too many sites that are any good. HTML Goodies is, however, the worst that I've seen. But this stuff isn't rocket science. All you need to do is go to the source. Just read, mark. learn and inwardly digest:

    The HTML 4.01 Specification
    http://www.w3.org/TR/html4/

    The CSS2 Specification
    http://www.w3.org/TR/REC-CSS2/

    Web Content Accessibility Guidelines 1.0
    http://www.w3.org/TR/WCAG10/
    “The power of the Web is in its universality. Access by everyone regardless of disability is an essential aspect.”
    —Tim Berners-Lee, W3C Director and inventor of the World Wide Web

  13. #13
    Join Date
    Jan 2003
    Location
    Atlanta, GA
    Posts
    571
    Charles, its not easy to read specs. Thats why tutorials are required. Did you start off HTMLing reading the specs? You dont know what to read and what not to, when you are a beginer. How will he make sense out of (for example)
    <!ELEMENT UL - - (LI)+ -- unordered list -->
    <!ATTLIST UL
    %attrs; -- %coreattrs, %i18n, %events --
    >
    <!ELEMENT OL - - (LI)+ -- ordered list -->
    <!ATTLIST OL
    %attrs; -- %coreattrs, %i18n, %events --
    >

  14. #14
    Join Date
    Nov 2002
    Location
    XYZZY - UK
    Posts
    1,760
    All I am saying about is Joe Burns uses a lot of proprietary code and yes there are a lot of errors on the HTML Goodies website.

    I learnt basic HTML within about half-an hour from reading a tag reference sheet and sitting with a web master for about ten minutes with a pencil and paper and he explained the basics.

    The rest I taught myself for a few months then I began following the W3C Recommendations but we are talking early 1999 when Netscape 3.0 was still popular.

  15. #15
    Join Date
    Dec 2002
    Location
    Calgary, Canada
    Posts
    2,653
    I guess every one is correct in what they are saying,we just have to consider this,that HTML goodies tuts were probably written in late 9dees,Heck even html did not have much in it by then, some 50+ tags may be?
    It doesnt sound fair to judge that on todays knowledge...if we do that then books written on physics 100yrs ago are jokes today..lol.
    The action that is debateable on HTMLGoodies behalf is that they should have updated their pages.


Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
HTML5 Development Center



Recent Articles