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Mastering PHP: Dynamic Web Development

Learn PHP, a server-side scripting language for dynamic web pages. Explore data types, variables, control structures, loops, functions, and more.

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Mastering PHP: Dynamic Web Development

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  1. PHP Teppo Räisänen LIIKE/OAMK 2011

  2. PHP • PHP is a programming language for making dynamic and interactive Web pages

  3. PHP • PHP stands for • PHP: Hypertext Preprocessor • PHP files end with • .php, .php3, .php4, .php5 or .phtml • In most cases its .php

  4. PHP • It is a server-side scripting language • This means that PHP code is executed on the server, not on the browser • JavaScript is executed on the browser • This also means that you have to put you PHP files into the Web server • They will not work e.g. From desktop

  5. PHP • PHP is open source • Free to download and use • PHP supports many databases • MySQL, Oracle, Informix, … • When you do dynamic Web pages you want to use databases • In practice you always need databases

  6. PHP example1 <?php Code here ?>

  7. PHP example2 <? Code here ?>

  8. PHP example3 <html> <head><title>PHP example</title></head> <body> <?php print ”<h1>Hello World</h1>"; ?> </body> </html>

  9. PHP example3 (in browser) <html> <head><title>PHP example</title></head> <body> <h1>Hello World</h1> </body> </html>

  10. Datatypes and variables • PHP is a ”loosely-typed” language • When you declare a variable, you don’t give datatype (but still variables do have datatypes) • When code is executed data type is defined according the contents • Example $somevariable=0; $somestring=”Teppo”;

  11. Basic datatypes • String • Integer • Float • Boolean

  12. Datatypes and variables • Variable declaring starts with $-character • You invent the name for the variable • Good practise is to give initial value • Example: $somenumber=0; $sometext=””;

  13. Operators = • = Operator • $firstname=”Charlie”; • $lastname=”Brown”; • $name=$firstname . $lastname; • $somenumber=1; • $someothernumber=3; • $total=$somenumber + $someothernumber; • $formvalue=$_POST[’fieldname’];

  14. Arithmetic operations • + addition • - subtraction • / division • * multiplication • % remainder

  15. Control structures • Conditional structures • If • Switch • Loops • While • For • Functions

  16. Basic syntax if (expression) { ... } else { ... }

  17. Example <? //Read value passed from HTML-form. $age=$_POST[’age’]; //Found out if user is minor or adult according to age. if ($age<18) { print ”Minor”; } else { print ”Adult”; } ?>

  18. Nested statements <? $grade=$_POST[’grade’]; If ($grade==0) { print ”F”; } else { if ($grade<3) { print ”C”; } else { if ($grade<5) { print ”B”; } else { if ($gade==5) { print ”A”; } else { print ”Not on scale”; } } } } ?>

  19. Logical operations • || OR • && AND • ! NOT

  20. Example <? $grade=$_POST[’grade’]; //If grade is not between 0 and 5 it is //not on scale. if ($grade<0 || $grade>5) { print ”Not on scale”; } ?>

  21. Example <? //Read value passed from HTML-form. $age=$_POST[’age’]; //Found out if user is minor or adult according to age. if (!$age<18) { print ”Adult”; } else { print ”Minor”; } ?>

  22. Loops • While • For • …

  23. While initialization while (condition) { //one or more statemens increment }

  24. Example (calculating compound interest using while) <? $loan=100; $interest=10; $year=3; $i=0; while ($i < $year) { $loan=$loan+ ($loan / 100) * $interest; $i++; } print ”Total amount of loan is $loan”; ?>

  25. For For (initialization;condition;increment) { //one or more statemens }

  26. Example (calculating compound interest using for) <? $loan=100; $interest=10; $year=3; for ($i=0;$i<$year;$i++); { $loan=$loan + ($loan / 100) * $interest; } print ”Total amount of loan is $loan”; ?>

  27. Functions • Two types of functions • Built-in (in PHP more that 700 prewritten functions available) • Custom • Gives well-defined structure to software • Adds reusability

  28. Function syntax Return value Name Parameters

  29. Example: mail() • Send email from you application without any spesific knowledge about email-protocols or low-level details <? $to="jouni.juntunen@students.oamk.fi"; $from=”teppo.raisanen@oamk.fi”; $subject=”The subject”; $message=”Test”; $headers='From:' . $from . "\r\n" . 'X-Mailer: PHP/' . phpversion(); if (mail($to,$subject,$message,$headers)) …?>

  30. Input validation with functions • Check if input given by user is numerical • Validation user following PHP-functions • floatval(), intval(), strval()

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