Browsers talk behind your back

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IM Question What's your name? What's your email address? Who do you work for? Do you have questions about the Web? Are there Net-related things you don't understand but think you should (and are too embarrassed to ask)? Send them in! Q: In an earlier column, you mentioned that cookies can't pull up information that you don't give them, but that there were other ways for the site to get that information. What did you mean by that?

A: Your browser and the Web server you connect to exchange a lot of information behind your back. When you're looking at a Web page, your browser is telling the server which browser it is, what kind of computer you're using and which operating system you're using. Your browser will even tell the server which site you visited last, and if it was a search engine, what terms you were searching for.

All this information is stored in the various log files kept by the server. Sometimes, though, your browser lies. Microsoft's Internet Explorer has a habit of pretending to be Netscape. So in the server's Agent Log, you might find a line like this: Mozilla/2.0 (compatible; MSIE 3.0; Windows 95).

What you've got is a user on a Win95 machine running Internet Explorer version 3.0, but as far as the server is concerned it's compatible with Netscape (Mozilla) version 2.0.

What does all this mean for you?

For the most part, this is a symbiotic relationship. The people who run the Web site get to find out some useful demographic information. For instance, if they see that most of their visitors come from Yahoo!, perhaps they'd want to advertise there, or on another one of the search engines. If they realize that all their traffic is using a browser at least as new as Netscape 2.0, they might go ahead and put their site in frames.

On your end, more and more sites are starting to have their servers figure out which browser you're using and give you a page that you can see well. In other words, they give you as much bang for your buck as they can. This is called content negotiation, or browser negotiation.

Soon, perhaps, one of two things will happen. Browsers will begin to standardize and support the same functions. Or sites will get so adept at handling this problem that you'll never again have to see options such as "If your browser supports frames, click HERE." Either way, you win as well.

Q: Sometimes, when I'm browsing the Web using Netscape, I'll be loading a page and it just won't come up. . . .

A: . . . and then you hit the "stop" button and it displays most of the page with one of the graphics broken, right? Many Web surfers have found this problem. The answer is simple, and not very helpful, but I'll share it with you, since you asked: Netscape likes to show tables all at once, and that's just the way it is.

Now, tables aren't necessarily data in charts. Sometimes entire sites are done in borderless tables so that the Web page designer has better control over how the pages look. However, if it gets caught trying to load even one little graphic, it might keep waiting for that to load instead of starting to display what it can of the page.

Why does this happen? Could be a couple things. The graphic file might actually be broken, but that's rarely the case. More likely the server is busy. When you point your browser at a page, you're connecting to it once for every file you're requesting. So the page, and each graphic, count as connections, as far as the server is concerned.

The problem arises because the server can handle only a certain amount of connections at once (based on how beefy the machine is that it's running on) and if you exceed that, your browser is going to just wait until the server has a chance to talk to it.

When you hit the "stop" button on your browser, you're telling it to give up waiting for the server. At that point, it goes ahead and shows you all the other stuff it's gotten (from all those other connections). And you can usually go about your surfing from there with no problem.

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