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IST210 1
Intro to PHP
IST210 2
Review: HTML & Tags
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How A Web Server Works
http://my.up.ist.psu.edu/zuz22/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 zuz22Return 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 PHP scripts– Programs that can generate dynamic HTML
results• Two types of scripts– Client side: running inside a browser• HTML
– Server side: running inside a web server• PHP
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Dynamic Page Example: Show Datehttp://my.up.ist.psu.edu/zuz22/date.php
<html><body><?php echo "Today is: ".date("m/d/y") ?></body></html>
<html>
<body>
Today is: 01/16/14
</body>
</html>
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Try it yourself
• Start Notepad or Notepad++• Create a PHP document to show the date
• Save as a php document, e.g. date.php• Place your php document on IST web space• Access it through URL:– http://my.up.ist.psu.edu/username/filename
<html><body><?php echo "Today is: ".date("m/d/y") ?></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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PHP Must Work Through a Web Server
• Check the date.php file in the folder• Right click the file in the folder, Open it with a
web browser, and see what happens.• Try “View Page Source”
• DON’T CLICK ON PHP PAGE DIRECTLY!!!• PUT PHP PAGE ON WEBSPACE AND VISIT
THROUGH WEB BROWSER!!!
http://my.up.ist.psu.edu/zuz22/date.php
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PHP and HTML
HTML PHP
Used to how to display text and other objects in a browser window
Used to dynamically create web pages written in HTML
Runs on the client side Runs on the server side
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About PHP (Hypertext Preprocessor)
• Created in 1994 by Rasmus 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 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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echo
echo means “print it to html”Double quotes pair “” define a stringSemicolon ; means the end of a sentence
<html> <body>
<?php echo "Hello World!";?>
</body></html>
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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 tags
<html> <body>
<?php echo "<h1>Hello World!<h1>";?>
</body></html>
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Exercise 1: echo
Step 1: Open NotePad++ and create “helloworld.php” in your webspace
Step 2: Using the codes above as reference, write codes to get the output on the right:• “Penn State” in bold• A break after “Penn State”• “red” in color red
<html> <body>
<?php echo "<h1>Hello World!<h1>";?>
</body></html>
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echo: Multiple PHP segments
<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>
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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>
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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 $x<br>"; echo "x is ".$x."<br>"; echo "y is $y<br>";echo "z is $z";
?></body>
</html>
1. Open your helloworld.php2. Input following codes3. Visit through web browser
http://my.up.ist.psu.edu/PSUID/helloworld.php
Try it
$x can be put insides quotes or outside quotes.When $x is outside of quotes, remember to use . to concatenate two strings
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Variables: Debug
<html><body>
<?php$name = "John";echo "My name is $Name.";
?></body>
</html>
Name is not shown. Where is the bug?
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Variables: Output Quotes
<html><body>
<?php$x = 1; //integer$y = 2.2; //float$z = "hello"; //stringecho "z is \"$z\"";
?></body>
</html>
In PHP, you can use \ to escape quotes.
quotes on hello
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Variables: HTML Tags
<html><body>
<?php$x = "Penn State";echo "I love <b>$x</b>";
?></body>
</html>
Penn State in bold
