7.What does a browser like internet explorer do? What other ways of looking at web pages are there?
Answers:
Pretty open ended question, but a few general thoughts should convey the gist of what's involved.
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history
Tim Berners-Lee, then at the CERN particle physics installation, and now of MIt and the WWWConsortioum at MIT, decided there had to be a better way to share information over a network better than the existing tools. So he invented a very simple Internet protocol HTTP, and began developing a piece of software which could handle that protocol. At the supply end, files are read from a hard disk and sent, using HTTP, to a client machine. The software at one end is Web server software (of which Apache is the most used, and Microsoft's IIS is the next most used; Sun and IBM are among other suppliers of Web server software). At the client end, the software is a browser. One of the earliest of these was Mosaic, developed at the University of Illinois and made freely available. Several commercial companies began with that browser and added additional features; among these was Netscape and Spry Inc. netscape gave away their browser and sold their Web server software and other auxilliary software. Spry's product was licensed by Microsoft and turned into Internet Explorer with which Microsoft was able to essentially put Netscape out of business (it was bought by AOL).
Instructions in the files (ie, Web pages) a server sends to a browser via HTTP are generally text files formatted in a speical purpose 'language' called HTML. It's odd as computer languages go in that HTML statements don't force a browser to do something, the same thing, every time. Instead, HTML layout statements are treated as suggestions to the browser. The browser attmepts to do what the HTML suggests, but is not obliged to do so. This is one of the reasons that Web pages don't always look the same from one machine to the next, as not every browser makes the same response to page content.
There are other browsers with some popularity. Opera was written in Norway, Firefox is an outgrowth of a project started at Netscape, and Konquerer, Gallion, etc are all open source developments in the Linux community. There are also some other browsers still being used (and developed) from early days; most notably, Lynx (which is text only -- does not manage images or any of the clever additions).
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changes in page content provisions
Since the Mosaic days, Web page display (and the formatting instructions in the pages) has acquired a good bit of new functionality. Among those are such things as Cascading Style Sheets, Dynamic HTML, cookies, JavaScript (aka ECMAScript), frames, and so on.
The various vendors (chiefly Netscape and Microsoft) invented new and unique Web content features, in part as a way to tie Web content to particular browaers and so to steal market share from other browsers. You will sometimes see comments on some Web pages saying something like "Best viewed with Internet Explorer v x.yz or later". There was also a parallel effort from the IETF and the W3C group to establish standards and prevent splintering of the Web market. Things are slowly converging, but there are still discrepancies between browser capabilities and the instructions sent them by Web servers.
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Since Web site sponsors and advertisers wanted to attract more attention (for marketing success, of course), they were interested in eye catching content. Not just text for them. No, indeedy; they wanted animations, polls, shopping carts, video, audio, etc etc. None of which were included in Berners-Lee's original protocol. Accordingly, a standard for browser plug-ins was developed, so browsers could display additional content beyond that in HTML, even extended HTML variants. Flash content, MP3 audio, (various other sorts of audio, including open source Ogg Vorbis), various sorts of video, PDF formatted files, assorted types of static images, and so on. This means that your browser typically has to have various things added from various other vendors to cope with that sort of content or this other.
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security
All of this active content in Web pages (Javascript, Java, ActiveX, primarily) has come with some inherent risks. Not every such routine will have been written by a benign and safe programmer. And in fact, the assorted malware producers have been quite active. The result is pop-ups, pop-unders, malware (keyloggers, activity trackers, and worse) as a result of using the Web (and letting such programs become established on your machine). Some browsers are worse than others, having a long history of insecutiryes of many kinds. Others are better. some allow dangerous types of content to be blocked easily, others make it very hard to do the same.
Users of Web browsers should keep a good anti-virus utility fully up to date and run it often (once a week is a common suggestion). They should do the same with at least two of the spyware remover programs. And they should install and properly configure, an adequate firewall to block Internet traffic of types you don't use (or need). Unwanted traffic is too often an attempt to attack your machien (or the operating system) or evidence that an attack has succeeded. Malware often establishes communication with some PrivatedataRus.com site from your machine, and this traffic should never be permitted.
Programs with good reputations include (for Windows);
AVG -- anti virus
Avast -- anti virus
Spy Bot -- spyware detector and remover
AdAware -- spyware detector and remover
Spy Catcher -- spyware detector and remover
ZoneAlarm -- firewall
Each is available in a free (lmited capability) version. Each is capable of good performance is configured properly and used sensibly. Poor configuration or erractic updata and use will do very little to protect your system.
Users of Windows and Internet Explorer should be particularly wary as both have a long and extensive history of insecurities.
Firefox is a new browser, and has had a much better experience thus far than IE. Opera is older, but has also been less insecure than IE.
Operating systems with better security records include Linux (my favorite is SuSE), the BSD variants (OpenBSD has very high committment to security throughout), or Apple's OS X (which is, underneath, another BSD variant).
Microsoft is preparing to release new versions of both IE and of Windows in the next year or so. There has been much comment from both Microsoft and observers that both will be much better with regard to security than prior versions. And, indeed, Bill Gates has announced at least twice in the past three years that 'security is job 1 at Microsoft'. Improvements in Windows and IE with these releases may reflect that committment.
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