Surfer's basic knowledge

This is very short manual contained common information about world-wide-web features and some specific information about browsers. It is an compilation of paragraphs from others manual. It has been created just to keep them together at one place.

Contents

[ Language ] :: [ Main Index ] :: [ Site Navigation ] :: [ Tutorials ] :: [ Downloads ] :: [ Contact ]

What URL is?

URL is acronym of "Uniform Resource Locator". Simply said, it is an address of file as well as instructions what to do with it.

Here are a few examples:

• http://www.freshcontent.com/content/1h4t9qceqsjqxvx/index.php?th=2&csp=l
• mms://204.17.45.35:554/3201-f-h.wmv
• http://www.viewsomepics.tk/members-area/week002/big2015.jpg
• rtsp://w905w69q:q0vvv0vrqwq4@content01.ppw-videos.net:554/cf23/3097_s331ts53.rm?mode=co&cloakport=8080%2c554%2c7070/streamid=1;seq=0;rtptime=0

URL consists with four basic parts:

1. Protocol (mostly HTTP) defines what to do with file. In case of HTTP just download, save and interpret (open and view, e. g.)
2. Server name (usually called host) identifies the computer that runs web server, or web server application. Usually it is a name, but combination of 4 bytes is also allowed and sometimes is used because it is quicker.
3. Next is the file name and its place (location) on the server path, or directories. This part can be shortened at HTML as we will see later.
4. The last one are parameters for that file. Usually there are parameters for query - as first example shows - and that parameters must be specified. But parameters for e.g. clip can also occur and in the most cases can be - and should be, in fact - omnitted.

For sure you mention that there are two other part on the URL examples.

1. Well, the first one is user-name and password authorization. It is allowed to specified them in this form. If we forgot about them, we will be asked. It is only convenient to you to provide authorization in shown form and to make this your habbit.
   If you get an "Invalid Syntax Error", please continue here for description.
2. The last one is overriding the standard communication port. When it has more than 3 digits, as you can see on the last example in parameter part, the first pair describes input port and the second output port. We will not go any futher - just stay at this. When it is given and you have no problems, let it be as is.

You can notice that almost all protocol of addresses written at Address bar, or reacheable during browsing the internet is HTTP. Well, world-wide-web, that part of internet services you usually use, is based on it. To be strict, it is based on HTML - which is the language described how to diplay a web-page , I mean its content, on user computer's viewer. That viewer is usually called browser and Microsoft Internet Explorer is one of them. Just not to complicate, once the information is displayed, why provide something another to transfer? So, HTTP together with HTML becomes universal esperanto of communication.

HTTP can transfer both text and binary data with almost perfect error-free aprovement. It means that you can get only exact copy of file from server. You even need not Net Transport. Just choose from pop-up menu "Save target as..." (or simillar) at your browser over URL link and wait until transfer complete.

[ Contents ] 

Truncated (relative) & scripted URLs

I mention that location at directory structure on web server can be shortened. Here are a few examples of this.

This is a part of imaginery HTML source code, which can be viewed directly from browser at any text editor. Usually standard Notepad or Write application are used. Please, focus your attention on the first (remark) line and on the bolded line beginning with src=. This technique is called "relative reference" and it is commonly used.

<!-- saved from URL: http://www.freshcontent.com/content/1h4t9qceqsjqxvx/index.php?th=2&csp=l>

<OBJECT ID="WinMedia"
classid="CLSID:22d6f312-b0f6-11d0-94ab-0080c74c7e95"
CODEBASE= "http://activex.microsoft.com/activex/controls/mplayer/en/nsmp2inf.cab#Version=5,1,52,701"
standby="Loading Microsoft Windows Media Player components..."
type="application/x-oleobject">

<PARAM NAME="FileName" VALUE="video.asx">
<PARAM NAME="ShowControls" Value="false">
<PARAM NAME="EnableFullScreenControls" VALUE="0">
<param name="AutoStart" value="1">
<param name="AnimationAtStart" value="1">
<param name="AutoSize" value="1">

<Embed type="application/x-mplayer2"
pluginspage="http://www.microsoft.com/Windows/MediaPlayer/"
src="../clips/am-van-l.vcs"
Name=MediaPlayer
AutoStart=0 Width=290 Height=300 autostart=0
</embed>
</OBJECT></TD>

Because source web-page URL is
http://www.freshcontent.com/content/1h4t9qceqsjqxvx/index.php?th=2&csp=l
and clip source is located at
"../clips/am-van-l.vcs",
the resulting URL for downloading this clip is
http://www.freshcontent.com/content/1h4t9qceqsjqxvx/clips/am-van-l.vcs

Much worse case is, when source path is kind of JavaScript or look as strange equation. This kind of URL is sometimes refered as "dynamical", because it is created on fly. Target file remains on the same place - only authorization procedures are dynamic at URL.

Here is one example when JavaScript and server-CGI-engine are used to build-up URL:

<td width="320" valign="top" align="left" height="240" bgcolor="#000000">
<object classid="clsid:CFCDAA03-8BE4-11CF-B84B-0020AFBBCCFA" id="vid" width="320" height="240" align="center">
<param name="_ExtentX" value="6350">
<param name="_ExtentY" value="4763">
<param name="SHUFFLE" value="0">
<param name="PREFETCH" value="0">
<param name="NOLABELS" value="0">
<param name="CONTROLS" value="ImageWindow">
<param name="CONSOLE" value="shrclip1">
<param name="LOOP" value="0">
<param name="NUMLOOP" value="0">
<param name="CENTER" value="0">
<param name="MAINTAINASPECT" value="0">
<param name="BACKGROUNDCOLOR" value="#000000"><embed name=vidx SRC="" type="audio/x-pn-realaudio-plugin" Console="shrclip1" Controls="ImageWindow" Height="240" Width="320" border="0" align="center" Loop="false" Autostart="false">
</object>
</td>

<!-- skipped >

<area href=JavaScript:startClip('http://www.web-prds2.com/yxy/v.cgi?fufipcfgqoxhu`flashoff`off04');
shape="rect" coords="1, 73, 99, 96">

And here is another one - JavaScript is used to create whole HTML web page source-code (incl. clip URL itself, which is provided through PHP engine):

<!-- skipped >

function VidWin(TheUrl) {
window.open(TheUrl, "VidWin", 'width=250,height=272,')
}

function NewMediaWin(CId) {
VidWin("/ff/adsl/feedlauncher.exe?IntId=0&L=Y&CustId=5855&Task=Template&Template=MediaWin.html&ContentNum="+CId+"&ContentName="+escape(VContent[CId].Title)) }

<!--skipped >

document.write('<Tr><Td Width="82" Height="24"><A Href="javascript:NewMediaWin('+XInt+');

[ Contents ] 

".../pic%20001.jpeg"

Maybe you already notice it, maybe not, there are sometimes a strange construction at URL. We will skip a serie of upper-case letters at its very end - it is an authorization in Base64 form, for curiosity. We will focus on "%xx" chars, which can be found anywhere.

Click on this link - a pseudo-art collage with logo, golden background and lens effect will open.
Its name on hard drive is "NTTA Gold&Lens.jpg".
But, you should see something different at Address bar - in concrete:
http://www.ntta.szm.sk/genimg/NTTA%20Gold&Lens.jpg
As you can see, space as (potentially) illegal char, has been renamed to its equivalent "%20".

Well, this %20 is code for space at Unicode. To be more precious, at UTF-8, i.e. lowest 256 chars of full 65 536 Unicode (UTF-16) chars. Any char at URL (except protocol) can be replaced with its UTF-8 code and a lot of sites do that when called through reference or engine. Net Transport also has this option.

You can try it for yourself - paste this link to browser window: http://www.ntta.szm.sk/genimg/NTTA%20Gold%26Lens.jpg.

Tip: If you are an Microsoft Windows XP user, open Character Map utility and choose any Unicode font - e.g. Arial. Note, that this codes are displayed at tooltip as well as at status bar at bottom left. For ampersand, it is text "U+0026"

Therefore this coding is not readable for most of population, you can, also, hide visited addresses, or at least your passwords, before human in this way. You can use this simple toy (195 kBy) - an utility, officially - which scramble URL or only password (if present). Full clipboard support implemented. See "Downloads" page for details.

However:

• you could get extremally long address as result, which can arise with miscellanous problems because of their truncating
• this address will be so strange, that it will focus someone attention
• the one, who is able find visited URLs, is able to figure out, what these codes are.
• your employer could not tolerate you this kind of fun

Tip: Instead of writting your e-mail address in its normal form, use HTML coded form, or text as "name (at) post-server.net", or better "name(on)post.net" - spam robots start to recognize that "(at)" fake.

And, by the way, what is the name of file at header?

[ Contents ]

Temporary Internet Files Directory

As I mentioned somewhere, HTTP always downloads files to your local computer. Well, these files browsers (not players!) store at special directory. Microsoft Internet Explorer use directory as following:

Windows98:
C:\Windows\Temporary Internet Files\Content.IE5\

WindowsXP:
C:\Documents and Settings\[current-user-name]\Local Settings\Temporary Internet Files\Content.IE5\

Opera 7 has its own cache in:
C:\Program Files\Opera 7\cache4\

In that directory and its sub-directories you can find all HTML documents, images, even flash-animation and Apple QuickTime movies. Sumarizing, everything what has been transported to you through HTTP protocol.

Microsoft Internet Explorer has this directory settings collected at Micorosoft Internet Explorer :: Tools > Properties :: (first tab) General. You can set its size or clear them manually. There is another one option (hidden) at the last tab Advanced of mentioned dialog box. Scrool the list to bottom to Security section and you will see an option Delete Temporary Internet Files on exit (or simillar). You should uncheck it, of course, and empty files manually from the first tab General.

Opera has all options collected at Properties dialog at tab History and Cache. You can pop-up through File > Properties, or quicker by pressing F12.

Please see also tutorial "My browser does not understand me ... why?!". There are some pictures.

[ Contents ] 

View source ...

Another basic skill is how to view source code of current web-page. You must remember that almost all of web-pages contained embeded media are framed. So when you choose "View source ..." command from Microsoft Internet Explorer pop-up menu or "Edit" submenu you must point your cursor to the correct frame. It is not always easy task to do, of course.

It is possible to change Microsoft Internet Explorer window in that way, that you will be unable pop-up menu through right-click or main menu will not be seen. In that case, just go to the upper mentioned Temporary Internet Files directory and find the information there. You can use even standard Find command of Microsoft Windows shell.

When you do not see "View source ..." command at pop-up menu, you probably hit the image which surround player window. In this case you can see commands "Save picture as ..." and "Set as background". Just try again to really click web-page space or try looking at Temporary Internet Files directory.

Anyway, you are looking for "*.ht*" file containing the text which is your clip-name, or probably clip-extension (e.g. text string ".wmv" or ".rm" or ".asx", etc.).

Opera 7 can prohibit pop-up windows, mouse tricks, generally all JavaScript (through File > Quick Preferences or F12 key) so right-click is always possible. You can view source from pop-up menu - choose Frame > View Source - or, quicker, press Alt + F3.

[ Contents ]

Cookies settings

Please see also tutorial "My browser does not understand me ... why?!". There are pictures. Or better, read a special tutorial about "Cookies".

Cookies are small text files used originally for personal authorization on post servers. As every human idea, this also has been expanded in time, and presently, cookies are used for authorization to restricted areas - sometimes. Because they are really just a text strings which stores values of variables, they are harmless for computers. They cannot scan anything, they cannot do anything because they are not an executable code.

The most important thing seems to me difference between "own" or "home" cookies and "external" / "foreign" / "third-party" or "alien" cookies. Third party cookies are sent by server which content is linked to the displayed page. Mostly it is an advert banner. That third-party cookie can be used only as identification from which URL are you really come from. Home cookies - which are sent by page you have displayed - could store much more. All cookies are accessible only for domain, which created them.

And one more myth: dissabling the cookies, does not guarantine you an anonymity.

Countless time I have been called to set-up cookies - task, which suddenly turns into restoring all general security setup. Cookies can be set at Micorosoft Internet Explorer :: Tools > Properties :: (third tab) Privacy! Do not enter, or change settings at second tab titled as Security! It is not necessary to go in there for changing cookies' security level! You should delete cookies after you finish with your internet session - definitelly, if you have not a NTFS hard disk. Interesting, that Microsoft Internet Explorer does not offer deleting cookies automatically - you must do it handly at first tab General - but, has set for default deleting files from Temporary Internet Directory ...

At least that particullar levels' description is really detailed. A middle level should be reasonable even for the most precautional among us. But, as I said before, there is no risk with accepting all cookies

Cookies at Opera 7 can be set at Preferences dialog (Opera 7 :: File > Preferences, or Alt + P short-cut) at Privacy tab. Options are by my opinion much more understable that those at Microsoft Internet Explorer. Quickly you can dissable all cookies throgh File > Quick Preferences :: Enable cookies, or by pressing F12 key. You can also set deleting new cookies automatically. I recommend you to Accept all cookies, but Do not accept a third party cookies as the most reasonable settings. You should check on both warnings, if the risk level seem to you be so high. If you meet a problems on framed sites, you must accept all cookies - even a third-party, and you should list them. Third-party cookies are then probably used as additional information from which URL you really come from.

Please look definitelly at Opera's Help. There is a document called Privacy (you can access it quickly through Contents at Link bar) with detailed description of the settings and a few external links about security.

Do not ever try to edit cookie?.* files ay Opera's directory!
If you want to browse through Opera cookies, please use a Opera 4 File Explorer by Josef W. Segur. You can download this util from Joe's Slim Software page (http://users.westelcom.com/jsegur/)

Most of tricks - such as ActiveX elements or browser plug-ins - are not allowed at Opera. However, you can still download and install a dialer!

[ Contents ]

Internet speed: kb vs. kBy

Please note, that internet connection bandwidth is always given in bits per second! Therefore 56k modem has theoretical capacity 56 kbps / 8 = 7 kBy per second. For the same reason, the clip prepared for transport through 10Mb LAN (network card) will need 10 x 1024 x 1024 x 60 / 8 = 78643200 by, i.e. 75 MBy of filesize per minute at maximum, as well as clip for 256 ADSL connection must be satisfied within 256 x 1024 x 60 / 8 = 1966080 by, i.e. (only) cca 1.875 MBy of filesize per one minute of run.

[ Contents ]

Firewalls and other sumplement tools

We are almost at finish. As the last thing, we will talk about firewalls. Firewall is an front-end application for internet and all communication comes through it. It knows everything as the first and it can take preventive actions by modifying HTML source code.

Firewalls are typical professional applications. They are small, tiny, sometimes dark and full of secrets, which do exactly what they are told to do. Nothing more, nothing less. So, they are also full of suprises and hard to set.

Probably one of the best firewall for Microsoft Windows is Proxomitron. It has a huge support, its own groups and lot of special settings available for free. Application itself is freeware, also. It will not help you only block out right-click-dissable codes, advert-banners, etc. but also to grab URL for media or even fake yourself. You can use it, but please remember, that no other application described below will not work - because Proximition will block localhost:8080 proxy.

The advert-removers are more friendly to ordinary users. The most sympathic to me is AdMuncher. Block-out most of JavaScripts tricks (mouse tricks, menu-hidding, self-focus, etc.) and almost all advert-banners. It has no special settings for ports and it can be used with any browser. Unfortunatelly, it is a shareware.

These two application can, of course, crush some sites. They will function only partially, or not function at all, or even they will be unreacheable for you ("Access denied" error). It can happened because the HTML source-code is modified. By my opinion, it is a small fee for services they provided - speed up browsing, save traffic volume, block unwanted pop-ups and, not at last, giving anonymity. When you encounter this situation, you should temporary deactivate them, hold the left Shift key and click Reload button on your browser. The page will be loaded again from server (normally is loaded from Temporary Internet Files directory). This will be probably not enough to log-in - if your problem resist, just wipe-out Temporary Internet Files. Choose from Microsoft Internet Explorer menu Tools > Internet options and on the first tab (General) click buttons Delete cookies, Delete files and Clear history. If this not help you, read what gone wrong exactly and why your access is denied.

There is Microsoft Internet Explorer "plug-in" called Avant Browser. It is compared to Opera functionality for Microsoft Internet Explorer. I do not know, because I have not tested it, yet. But if this is true, this freeware can be good choice and definitelly worth to install.

[ Contents ]

Error Pages

Please see also tutorial "My browser does not understand me ... why?!". For futher and detailed information.

Sometimes you can browse to the page 404.htm. This should not happend when you browse normally over domain, because in this way Apache server informs you that you try to access a broken link. File you have just requested does not exist on server anymore.

Apache server can inform you about a few other moves, which it recognizes as illegal for you. These pages can be standard generated pages (header and single line of text), but can be also overwrite by web-master with custom design. Sometimes, they are an piece of art. Important is an URL at address-bar. Is it finish with four-hundred-something? Or five-hundred-something? So, it is an error page.

Here is a short - not full - table of Apache servers common error codes and their meaning:

Your browser can show also one of the following errors:

[ Contents ]

Invalid Syntax Error

As I mentioned, authorization duo username:password can be a part of URI. Address written to address bar has in this case following structure: protocol://username:password@host/path/filename. It looks, e.g. like http://asd123xcvbnm:987a654b321c0@www.restrict2entry.com/memberssectiononly/.

Microsoft disabled this form of authorization for Microsoft Internet Explorer at the latest service pack. Both for Microsoft Windows XP and for Microsoft Internet Explorer only. When you use this form, you will get - as usually, very detailed description: “Invalid Syntax Error”.

You have to write only URL without authorization, and appropriate password should be enter when prompted.

A few individuals hidden behind pseudonyms said, that Microsoft wants to disable password piracy, which grown rapidly with wireless connection to internet. It is very easy to monitoring internet traffic at free-of-charge frequencies, because only a few ISP providers use an encryption. I personally doubt, that this is true reason. It is a fact, that this reference can be easily misappropriate – and it is heavily misused at free-access sites! There are a few examples mentioned at original Microsoft Knowledge Database Article Q834489.

Please download this registry update file and install it. If you do not understand, please read the whole article here - or better download it here.

[ Contents ]

Updates

2004-07-25
More detailed description of Cookies

2004-02-28
Invalid Syntax Error of Microsoft Internet Explorer added.

2003-07-06
Temporary Internet Files - extended about directory settings. Error pages - tables replaced and extended. Cookies - added. Link to "My browser does not understand me - why?!" at http://www.ntta.szm.sk/Tutors/ErrSites.htm is added to some chapters, because of pictures. ".../pic%20001.jpeg" chapter added, with "URL Scramble" application.

[ Contents ]