Webpage Guide

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Revision as of 19:14, 26 October 2012 by Igor (talk | contribs) (→‎Potential problems)
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This page provides a basic tutorial on how to manually create your own web page on the Math department server.

Setting up a web page

Hello World page

Below is a minimal example of well formed (W3C-compliant) HTML document. It includes a handy HTML markup validation button. 

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<title>Hello World</title>
<meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
<meta http-equiv="content-style-type" content="text/css"/>
</head>
<body>
  <p>Hello, World!</p>

  <p>
    <a href="http://validator.w3.org/check?uri=referer"><img
      src="http://www.w3.org/Icons/valid-xhtml10"
      alt="Valid XHTML 1.0 Transitional"
      style="border: 0; height: 31px; width: 88px" /></a>
  </p>
</body>
</html>

Unix command line method

This section explains how to create a webpage from a Unix terminal session, assuming you already know a little of Unix commands and HTML. For an introduction to HTML, see below.

  • First you need to login to login.math.berkeley.edu (a.k.a. panda) via SSH terminal emulator or start the Terminal application (menu item: Applications/Accessories/Terminal) if you are logged in to Math thin client server beyonce.math.berkeley.edu.
  • In your home directory, you need to create a directory called public_html with the appropriate permissions. You can do this from a math department computer or over SSH by typing:
mkdir public_html
chmod 755 public_html
  • All files and directories for your webpage should be placed in the public_html directory, and the directory and all its contents must have their permissions set so that others can read the files and read and execute the directories.
  • Additionally, inside public_html, you should have a file called index.html, which will be your homepage, i.e. the first page that pops up when someone visits your website.
  • You can edit this file with any Unix editor. To use xemacs, for example, type
xemacs public_html/index.html
  • An alternative to xemacs is pico, which is used for writing emails in alpine. Other popular command line editors are vi, vim, and nano. When you're done, type chmod 644 public_html/index.html to give the file the right permissions. Your page should now be visible at /~USERNAME/. You can create other pages by creating other files in the public_html directory. For example, the file public_html/math1b.html will have the URL /~USERNAME/math1b.html.

For more information on managing files on the math department's file server and what the permissions mean, see the page on file management.

GUI method

This method works from any Math thin client computer connected to beyonce.math.berkeley.edu. The steps are essentially the same but no knowledge of Unix commands is necessary.

  • Start GUI file manager (a.k.a. Nautilus): either double-click on home folder icon on your desktop or select Home Folder from Places menu.
  • Create public_html directory in your home: select Create Folder from right-click menu in the Nautilus window.
  • Verify the directory access permissions: right-click on newly created public_html icon and select Properties, then select Permissions tab in the Properties dialog window. Make sure the owner can "create and delete files" while group and others can only "access files".
  • Create an empty HTML document in the public_html directory: double-click on the public_html icon and select Create Document (Empty File) from right-click menu in the Nautilus window. Call the empty document index.html.
  • Similarly verify the index files permissions: right-click on newly created index.html icon and select Properties, then select Permissions tab in the Properties dialog window. Make sure the owner can "read and write" while group and others can "read-only".
  • Edit the index document: right-click on newly created index.html icon and select Open with "Bluefish Editor" (or chose any other GUI editor you are comfortable with).
  • You may copy the above sample page and paste to the editor window, save the document and view it in the web browser (URL: /~USERNAME/index.html).
Note: All your changes become visible to the world the moment you save the file. It is not recommended to use this error and try approach with the index.html file. Use a different file instead, e.g. test.html, and rename it to index.html when you are satisfied with changes.

Upload method

This method works from any (non-department) computer. Again, the essential steps are the same but you edit your HTML code on a personal laptop or home computer and upload ready-made web pages to the public_html subdirectory of your Math department home directory.

  • Login to login.math.berkeley.edu via SFTP and go to you home directory: use any GUI or text-based SFTP client software available for your platform.
Note: Here are some popular free SFTP clients: Fugu for Mac, WinSCP for Windows. Linux GNOME environment comes with built-in "Connect to Server" feature as well as an amazing text-based utility called lftp.
  • Create public_html directory in your home if it does not exist already.
  • Upload HTML documents, CSS style sheets (if any) and other files and folders (as needed) to remote public_html directory.
  • Make sure that the remote directories and files are not writable by group and others.

Potential problems

Some things which might go wrong when you try to view the page in a browser:

  • Error 403: This means that you don't have the permissions set correctly or the index.html file is missing. To make sure the permissions are correct for your homepage, type on a terminal command line:
chmod 755 ~/public_html
chmod 644 ~/public_html/index.html
  • Error 404: This means that the web server couldn't find your file at all. Make sure you have the files in the public_html directory.
  • Error 403 while accessing a subdirectory of public_html: Again, this means incorrect permissions or missing index.html file.
Note: The automatic directory listing has been recently turned off for security reasons.

Basic HTML

Each individual webpage on your site corresponds to a file of the form name.html . An HTML file just consists of plain text with a couple commands that tell the browser to do something to the display (for example, make the text bold font). Just like in LaTeX, there are some special characters that tell the browser "I am giving you a command"; they are <, > and /. Every command takes the form <command>, and most commands also allow you to turn them off by typing </command>. For example, if you want to turn on bold font, type <b>. When you are done typing the text that you'd like bold, turn off bold font with </b>.

The nice thing about HTML is that it is very forgiving--even if you make a mistake it will try its best to render something in the browser. This makes it easy to see the mistake and usually makes it easy to see how to fix the mistake too. Commands are case-insensitive.

  • <HTML> In principle, every .html file should begin with <HTML> and end with </HTML> to let the browser know that you are going to use HTML commands. But if you plan on just writing plain text, then this is not necessary.
  • <Title> This is the title of the webpage--what appears in the top bar of the browser window. Be sure to turn it off after using it, so that all the text doesn't appear in that one bar!
  • <Body> This delineates the body of the webpage: all the text, images, etc that you want to appear on the page should go in between the Body on and off commands.
  • <br> and <p> Notice that if you just type text in an HTML file, the browser will ignore all enter keystrokes. In general, browsers treat extra "whitespace" as just one click of the spacebar. To tell a browser that you would like a line break, use br. If you would furthermore like a blank line to start of the next paragraph of text, use p instead.
  • <b>, <i>, <u>, and <s>. Bold, italic, underlined and strikethrough text, respectively.
  • <font size="n" color="rrggbb" align="rcl"> Set many optional properties on the font. Size takes a number as an argument; align takes one of "right", "center" or "left" as its argument; and color takes an RGB value as its argument. An RGB (red-green-blue) value is simply a 6 digit base-16 number, which means the digits can take any value from 0 to 9 and A to F. The first two digits give you the amount of red, the next two give you green, the last two give you blue. For example, fa8072 yields a tasty salmon color. To turn all these properties off, you just have to type </font>.
  • <body background="file/URL" bgcolor="rrggbb" link="rrggbb" vlink="rrggbb"> The optional properties for the BODY command, which set the background and the colors of links. Background takes either a filename (from you public_html directory) or a URL of another website, and sets that as the background. If it is too small of an image, it will be tiled. Bgcolor sets the background to a solid color if you don't want an background image. It, like link and vlink, takes an RGB value to set the color. Link is the color of an unclicked link; vlink is the color of a clicked link.
  • <img src="file/URL"> For inserting an image onto you webpage. The argument for src is either a filename or pathname for an image in your public_html directory, or else a complete URL to an image elsewhere.
  • <A HREF="URL">text</A> . For links to pages on your site or on other sites. This can also be used to link to a PDF file or some other file for download. The URL is either the full URL for some other website (including the initial http://), or else just a pathname for an html file in your public_html directory. When the link is clicked, this is the page the browser directs you to. "Text" is just the text of hyperlink. For example, you may want the text to say "Solutions to Homework 9", but the URL will be something like "solutions9.pdf".
  • <mailto: emailaddress>. Creates a link that when clicked will open up the user's email program to send an email to "emailaddress". It is highly advised that you do NOT use this, but instead use Javascript to conceal your email address from spammers. See below for ways to conceal your email address.

Learning More HTML

If you come across a web page and want to know how they did that, you can try looking at the webpage's source. Most browsers have a View Source option in their menu (e.g. Firefox has a convenient keyboard shortcut Ctrl-U for source viewing); this will bring up the HTML page which you can examine.

Also, there are many HTML tutorials and reference guides. One tutorial can be found at w3schools.com.

There are also free templates (a.k.a. CSS style sheets) available online. A particularly good site can be found at openwebdesign.org.

Concealing Your Email From Spammers

Spammers use automated programs called webcrawlers to browse through webpages searching for email addresses. If your email address is just written in plain text in the HTML file (especially if you use the mailto command) a webcrawler will pick it up and you will get more spam. There are a few ways to conceal your email address from webcrawlers. We have listed them below, in increasing difficulty of implementation (which also happens to be increasing order of strength).

  • Use words instead of punctuation. Many primitive webcrawlers are designed to look for the @ symbol and then copy the text around it. If you write words, like mgsa AT math DOT berkeley DOT edu, many webcrawlers will not realize it is an email address. This is a pretty commonly implemented trick to fool webcrawlers, but it's easy for a spammer to adapt and include searches for "AT <word> DOT" and still find your email. However, if your email address has some natural form, then you can use that in the description and webcrawlers will not be able to get it. For example: my last name AT math DOT berkeley DOT edu.
  • Another way to fool webcrawlers who search for @ is to replace @ with an image of the symbol @. Webcrawlers cannot "see" what an image says, so this method completely works. The only downside is that someone trying to copy your email address has to remember to add the @ symbol. A large selection of images can be found doing an Google advanced image search for "at.gif" with the requirement that all images be small size.
  • Javascript is used to embed programs in HTML and we can use it in a very simple way to conceal the mailto: command from spammers. This is the method used by the math department and MGSA to hide email addresses on their websites. This method also allows viewers to simply copy and paste email addresses into their email programs. To use it for a math.berkeley.edu email address, copy the following code into your HTML file where you would normally have a mailto: command:
<script type="text/javascript">
GoFish=new Array()
GoFish[0]="%3c%61%20%68%72%65%66%3d%" + "22%6d%61%69%6c%74%6f%3a"
GoFish[1]="YOUR_NAME_HERE" + "%40%6d%61%74%68%2e%62%65%72%6b%"
GoFish[2]="65%6c%65%79%2e%65%64%75%22%3e" + "YOUR_NAME_HERE"
GoFish[3]="%40%6d%61%74%68%2e%62%65%" + "72%6b%65%6c%65%79%2e%65%6"
GoFish[4]="4%75%3c%2f%61%3e" + ""
OutString="";
for (j=0;j<GoFish.length;j++){
OutString+=GoFish[j];
}document.write(unescape(OutString));
</script>

In the two spots where it says YOUR_NAME_HERE you have to put the hexadecimal code for your user name. This hex generator will output the hexadecimal code for your user name.

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