Scott Marino MSMIS Summer Session Web Site Design and Authoring Session 13 Scott Marino

MSMIS Summer Session Topics Introduction to PHP PHP Syntax Forms and Form Elements Numbers and Strings Conditionals and Loops Arrays and Regular Expressions

Scott Marino MSMIS Summer Session Introduction to PHP Originally called Personal Home Page (PHP) Now called Hypertext Preprocessor Created in 1994 as an open source project Server-Side execution Cross Platform compatible –Unix, Windows, Mac, OS/2 HTML embedded

Scott Marino MSMIS Summer Session Why use PHP Better, faster, and easier to learn than CGI, ASP, and JSP PHP does much more than you can do with basic HTML PHP was written specifically to create web pages –Perl, VBScript and Java were adapted to work on the web Can’t do everything that other programming languages can

Scott Marino MSMIS Summer Session Basic Syntax Directive to PHP to interpret the code between the tags and perform the instructions –The phpinfo function prints installation information about PHP –Every instruction ends with a semicolon Files are saved with a.php extension instead of.htm for Apache

Scott Marino MSMIS Summer Session Basic Syntax print(“Hello there”); –Print function to embed text or html into the web page // or # denotes a single line comment /* (several text lines) */ for commenting multiple lines

Scott Marino MSMIS Summer Session Basic Syntax Variable Types –Number –String –Array $num_var = 1; $float_num_var = 1.2; $string_var = “PHP is cool!”; Look at phpinfo(); for available environment variables

Scott Marino MSMIS Summer Session Forms and PHP PHP can access data elements from a form Instead of calling a cgi script in the form action, the action will point to a PHP page Can use both post and get methods (on the form) print(“$lname”); –Prints the PHP variable from the form field name

Scott Marino MSMIS Summer Session Formatting Numbers To print a $ sign, you must “escape” it –print (“total dollars = \$$total_dollars”); The printf(); function can format numbers for printing Supports mathematical precedence with the use of parenthesis Has built in functions like round(); and abs(); Can create random numbers with srand(); and rand();

Scott Marino MSMIS Summer Session String Formatting trim(); removes leading and trailing spaces from string fields –ltrim(); and rtrim(); functions are available $string = $astring. $bstring; $string = $astring. “ “. $bstring; urlencode(); is used to convert characters to the proper format for a url urldecode(); is used to convert an encoded url back to standard format

Scott Marino MSMIS Summer Session String Formatting strtok(); Creates a string from a token –$f_name = strtok($fullname, “ “); substr($string,0,10); –Parses the first 10 characters of the contents of $string starting with position 0 strlen($string); –Counts the number of characters in $string

Scott Marino MSMIS Summer Session Conditionals if (condition) { true action; } else { false action; } If the condition or test results in “true” then execute the “true action” else execute the “false action”

Scott Marino MSMIS Summer Session Conditionals if (condition) { true action; } elseif (condition) { true action; } else { false action; } The elseif allows for additional levels of conditions to be checked

Scott Marino MSMIS Summer Session Conditionals switch ($state) { case "AL": print ("Alabama"); break; ….. default: print(”State of Confusion"); Used for a longer list of conditions than is easily handled with elseif

Scott Marino MSMIS Summer Session Looping while (condition) { statements; } do { statements; } while (condition); for ($I = 1; $I <= somecount; $I++) { statements; }

Scott Marino MSMIS Summer Session Arrays $list = array(“apples”,”peaches”,”pears”); –Creates a simple array with elements in array positions 0,1, and 2 $list = array(1=>“apples”, 2=>”peaches”, 3=>”pears”); –Creates an indexed array with elements in array positions 1, 2, and 3 $list[] = “grapes”; –Adds element “grapes” to the end of the array

Scott Marino MSMIS Summer Session Regular Expressions PHP Supports Regular Expressions ereg(“pattern”,”string”); –ereg is a case sensitive match $pattern = “pattern”; $string = “string”; eregi($pattern, $string); –eregi is a case insensitive match