A short note about PHP:

PHP has following characteristics:
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a script that executes server side
user only sees result, never the code--> compare the index.php file and the 
source code for the websit
not an extension for hmtl
often used as html extension

PHP simple functionalities:
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simple echo line
-----------------
php prints simple text
embedding what is generated from php in html
<?php echo 'PHP says: Hello World!</p>'; ?>
starts with <? 
ends with ?>
a lot like perl
$, '', ""

include line
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like #include in c
<?php require("header.php"); ?>
main use for include header files
you can also include functions using php

formtest.php
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<form action="formtest.php" method="post">
html creates form
once user clicks on submit, form sent to the php file
$_POST is a php variable

counter
--------
code starting with 
<?php
  $counter_file = "./counter.txt";
counter value from counter.txt file
possible problem if mutiple users try to access the counter.txt file
simultaneously

use table to draw boxes
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width="<?php echo $bar1 ?>%
use php to set length

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assignment (optional, can be used as extra credit) 
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poll site 

Page 1:
--------
Which CPU is the best
(radio buttons)
Opteron
Athlon 64
Pentium 4
Power 5
Other
(submit button)
submit  
view result

Page2:
------
Results:
CPU name (Bar generated with table) percentage

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php makes cookie handling easy
Extra credit:
1. cookie to avoid multiple voting from the same user
2. "flock" php code so that simultaneous users won't clash source.txt

keyword to goole:
php cookie
php forward