resources
helpful hints - General
JavaScript is a scripting language most often used for client-side web development. The primary use of JavaScript is to write functions that are embedded in HTML pages and interact with the Document Object
Model (DOM) of the page. Some simple examples of this usage are:
- Opening or popping up a new window with programmatic control over the size, position and 'look' of the new window (i.e. whether the menus, toolbars, etc. are visible).
- Validation of web form input values to make sure that they will be accepted before they are submitted to the server.
- Changing images as the mouse cursor moves over them.
Because JavaScript code can run locally in a user's browser (client side as opposed to server side), it can respond to user actions quickly, making an application feel more responsive. Furthermore, JavaScript code can detect user actions which HTML alone cannot, such as an 'onClick' or 'onmouseover' event.
Bits and Bytes
A little perspective put to the numbers.
Byte: |
8 Bits, or a single character, ~10 bytes in a single word |
Kilobyte: |
1,000 bytes, two kilobytes is one typed page. |
Megabyte: |
1 million bytes, a small novel |
Gigabyte: |
1 billion bytes, a pickup truck filled with paper documents |
Terabyte: |
1 trillion bytes, a research library is ~2 terabytes. |
Petabyte: |
1 quadrillion bytes, the web is ~10 petabytes. |
Exabyte: |
1 quintillion bytes, two exabytes is all data produced annually. |
Google Search Hints
Number of Pages Indexed
Number of Backlinks
Total Number of Links
Yahoo Search Hints
Number of Backlinks
Robots.txt Usage
The "robots.txt" file is informative to robots (spiders) who visit a specific site. Well written robots will search a root directory for this file upon their initial visit. Within the robots.txt file you can specify a specific User-agent (e.g. googlebot) or use a wildcard ('*'; to specify all robots).
Examples
User-agent: *
Disallow:
The above specifies that all robots can visit all files.
User-agent: *
Disallow: /cgi-bin/
Disallow: /img/
The above specific that all robots can visit all files accept those found in the cgi-bin and img directories.
User-agent: googlebot
Disallow: example.html
The above specifies that googlebot should not visit example.html.