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IST210 1
IST 210: PHP BASICSIST 210: Organization of Data
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Previous Classes Review
HTML Basics
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Place Your Page on Web• Step 1. Go to your webspace folder
• Open any folder. On the left-hand side, expand Computer, click on “IST UP Webspace”.
• Step 2. Place your helloWorld.html in the webspace folder
• Step 3. Open a browser, visit
my.up.ist.psu.edu/YourPSUID/helloWorld.html
If I put helloWorld.html file on my desktop, does this work?
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IST 210: PHP BASICSIST 210: Organization of Data
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How A Web Server Works
http://my.up.ist.psu.edu/zul17/HelloWorld.html
Find the IP address of the server my.up.ist.psu.edu
Send the request to the server
HelloWorld.html<html>
<body>
Hello World!
</body>
</html>
Get file: helloworld.htmlFrom folder zul17Return to user
User Web Server
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Problems with HTML• Static pages
• Cannot provide dynamic contents based on user preferences and interest
• Users often need different things in different conditions• Google• Facebook• ANGEL, webmail
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Dynamic Web Contents• Through scripts (e.g., PHP)
• Programs that can generate dynamic HTML results
• Two types of scripts• Client side: running inside a browser• Server side: running inside a web server
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Hello World in PHPhttp://my.up.ist.psu.edu/zul17/helloworld.php
<html><body>
<?phpecho "Hello World!";
?></body>
</html>
<html>
<body>
Hello World!
</body>
</html>
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Dynamic PHP Example: Show Datehttp://my.up.ist.psu.edu/zul17/date.php
<html><body><?php echo "Today is: ".date("m/d/y") ?></body></html>
<html>
<body>
Today is: 08/27/12
</body>
</html>
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How It Works: More Details• When a browser requests an HTML file, the HTTP
server returns the file • When a browser requests an PHP file
• The web server passes the request to a PHP interpreter• The PHP interpreter reads the PHP file, line by line, and
executes the scripts in the file• Finally, the executed result is returned to the web server, which
delivers HTML contents to the browser
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Differences Between PHP and HTML• Which language is used for display format?
• HTML
• Which language is programming language?• PHP
• Which runs on the client side (the system on which the page is being viewed) ?• HTML
• Which runs on the server side (the system from which the page comes)?• PHP
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PHP and HTML• HTML
• is a language used to describe to a browser how to display text and other objects in a browser window
• NOT a programming language• works on a client computer (the system on which the page is being
viewed)
• PHP • is a scripting language, and can be used to create HTML page• runs on the server (the system from which the page comes)• is a full-fledged programming language
• programming languages: C, C++, C#, JAVA, Python
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About PHP• Created in 1994 by Rasmu Lerdorf• A simple set of Common Gateway Interface binaries
written in the C programming language• Originally used to track visits to his online resume
“Personal Home Page tools” • PHP:
• Originally: Personal Home Page; • Now: Hypertext Preprocessor
• PHP is used as the server-side programming language on 75% of all Web sites• E.G. Facebook, Wikipedia
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PHP – Getting started• PHP code segments are mixed with HTML source• Escaping from HTML (To tell PHP processor: this is
PHP code)• A PHP parser starts to execute codes when it
encounters a start tag• The parser does not process non-PHP code• Two options indicating the embedded PHP codes
<?php … ?> (<? … ?>)
<script language=“php”> … </script>
<html><body><?php echo "Today is: ".date("m/d/y") ?></body></html>
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PHP – Getting Started
• Step 1. Open a NotePad++• Step 2. Input codes• Step 3. Save it to
“helloworld.php” to your webspace
• Step 4. Open a web browser, and visit• http://
my.up.ist.psu.edu/PSUID/helloworld.php
<html><body>
<?php
echo "Hello World!";?>
</body></html>
Try it
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PHP Must Work Through a Web Server
• Find the helloworld.php file in your webspace• Double Click the file in the folder and see what happens
• Now visit through your web browser:http://my.up.ist.psu.edu/PSUID/helloworld.php
• What happened? • PHP must work thru a web server!
• Try “View Page Source”
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echo – deep dive.
<html><body>
<?phpecho
"Hello World!";?>
</body></html>
echo means “print it to html”Double quotes pair “” define a stringSemicolon ; means the end of a sentence
Semicolon
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echo
<?phpecho "Hello
World!";?>HTML is not a strict language.It is OK to only have PHP part.
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echo
<html><body>
<?phpecho "<h1>Hello
World!<h1>";?>
</body></html>
Try it
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echo: Exercise 1
<html><body>
<?phpecho “<h1>Hello
World!<h1>";?>
</body></html>
Think
How to modify codes to get the output on the right ?• Penn State in bold
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echo: Exercise 1 Answer
<html><body><?php
echo "Welcome to <b>Penn State</b> <br>";
?></body>
</html>
How to modify codes to get the output on the right ?• Penn State in bold
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echo: Exercise 2
<html><body>
<?phpecho “<h1>Hello
World!<h1>";?>
</body></html>
Think
How to modify codes to get the output on the right ?• A break after “Penn State”• Red in color red
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echo: Exercise 2 Answer
<html><body><?php
echo "Welcome to <b>Penn State</b> <br>";
echo "I like <font color=red> red </font>";
?></body>
</html>
How to modify codes to get the output on the right ?• A break after “Penn State”• Red in color red
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echo
<html><body>
This is HTML part. <br>Hello world in HTML. <br><?php
echo "Hello World in PHP!<br>";
?>Back to HTML again! <br><?php
echo "Hello World in PHP again!";
?></body>
</html>
Try it
Multiple PHP segments
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echo
• echo — Output one or more strings• String is defined in a pair of " "• String concatenate using .
<html><body>
<?phpecho "Welcome "."<br>"."Hello World";
?></body></html>
Try it
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echo
echo "Welcome "."<br>"."Hello World";
echo "Welcome <br> Hello World";
echo "Welcome";echo "<br>";echo "Hello World";
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Variables• Data types
• Similar to C++ or Java• Int, Float, Boolean, String• Array (next class), Object (not covered in our class)
• Variables: a symbol or name that stands for a value• PHP variables start with $• You can use variables without defining the type
• $x = 5;• $pi = 3.14;• $name = "George";
• Name your variables in meaningful ways• $s = "matrix" vs. $servername = “matrix”
• Case sensitive!• More data types
• http://php.net/manual/en/language.types.php
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Variables
<html><body>
<?php$x = 1; //integer$y = 2.2; //float$z = "hello"; //stringecho "x is $x"; echo "x is ".$x;
?></body>
</html>
1. Create a test.php in your webspace2. Input following codes3. Visit through web browser
http://my.up.ist.psu.edu/PSUID/test.php
Try it
$x can be put insides quotes or outside quotes.When $x is outside of quotes, remember to use . to concatenate two strings
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Variables: Exercise 1
<html><body>
<?php$x = 1; //integer$y = 2.2; //float$z = “hello”; //stringecho "x is $x";
?></body>
</html>
Think
How to modify codes to get the output on the right?
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Variables: Exercise 1 Answer
<html><body>
<?php$x = 1; //integer$y = 2.2; //float$z = "hello"; //stringecho "x is $x <br>";echo "y is $y <br>";echo "z is $z <br>";
?></body>
</html>
How to modify codes to get the output on the right?
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Variables: Exercise 2
<html><body>
<?php$x = 1; //integer$y = 2.2; //float$z = “hello”; //stringecho "z is $z";
?></body>
</html>
Think
How to modify codes to get the output on the right?
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Variables: Exercise 2 Answer
<html><body>
<?php$x = 1; //integer$y = 2.2; //float$z = "hello"; //stringecho "z is \" $z \"";
?></body>
</html>
How to modify codes to get the output on the right?
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Variables: Exercise 3
<html><body>
<?php$name = "John";echo "My name is
$Name."; ?>
</body></html>
Debug
Name is not shown. Where is the bug?
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Variables: Exercise 3 Answer
<html><body>
<?php$name = "John";echo "My name is
$name."; ?>
</body></html>
Variable name is sensitive. Should be $name not $Name
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Variables: Exercise 4
<html><body>
<?php$x = "Penn State";echo "I love $x";
?></body>
</html>
Think
How to make the string in bold?
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Variables: Exercise 4 Answer
<html><body>
<?php$x = "Penn State";echo "I love <b> $x
</b>"; ?>
</body></html>
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Expressions• Any legal combination of symbols that represents a
value• Each programming language and application has its own rules
for what is legal and illegal• Every expression consists of at least one operand and
can have one or more operators • Operands are values• Operators are symbols that represent particular actions
• Examples• 5+3• $x*$y• $x > $y • $x <> $y• $x == $y
• More:• http://www.w3schools.com/php/php_operators.asp
A==B: boolean result, true or falseA=B: assign variable B’s value to
variable AA very common mistake:if (x = 1) then … This is always true!
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Functions
<html><body><?php echo "Today is: ".date("m/d/y") ?></body></html>
1. Create a date.php in your webspace
2. Visit it through web browser
Try it
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Functions
<html><body><?php echo "Today is: ".date("m/d/y") ?></body></html>
1. Create a date.php in your webspace
2. Visit it through web browser
Try it
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Functions
<html><body><?php echo "Today is: ".date("m/d/y") ?></body></html>
1. Create a date.php in your webspace
2. Visit it through web browser
Try it
String concatenation
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Functions<?php <html>
<body><?php
echo "Today is: ".date("m/d/y").”<br>”;echo “A random number in
[1,10]”.rand(1,10).”<br>”;$name = "John";echo "The length of string \" $name \" is
".strlen($name); ?>
</body></html>?> More string functions
http://php.net/manual/en/book.strings.phpMore math functionshttp://php.net/manual/en/ref.math.php
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Learn more about PHP• Reference websites
• http://en.wikibooks.org/wiki/PHP• http://php.net/manual/en/index.php
• Learn from experience• Try it yourself!• Try different ways to write the codes.• Learn from debugging
• Learn from examples• Search “php echo” on google• http://php.net/manual/en/function.echo.php• Learn from the example
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Reminder• Assignment 2 due on Monday Sept 14th 11:59PM!
