Writing Web Pages By Shyam Gurram. Agenda Writing Web Pages Delimiting PHP Program Units. Displaying Output to Web Pages Putting Comments in PHP Programs

Writing Web PagesBy

Shyam Gurram

Agenda

• Writing Web Pages

• Delimiting PHP Program Units.

• Displaying Output to Web Pages

• Putting Comments in PHP Programs

Writing Web Pages

• As we said discussed in the previous chapter, PHP is a server-side scripting or programming language. The primary purpose of server-side programming language is to generate HTML web pages. This language can be used to generate a complete a web page but is generally used as part of static or dynamic web page.

• We need to learn the following concepts to create a Web pages in an effective manner.

Delimiting PHP program units.

Displaying output to web pages.

Putting comments in PHP programs.

Delimiting PHP Program Units.

• We have four possible styles to use for embedding PHP in your web pages.

Default style ( Using the tags <? php and ?>)

HTML style script delimiters (<script language = “PHP”> and </script>)

Short tags (<? and ?>)

ASP-style tags (<% and %>)

• Among the four short tags and ASP-style tags save very little and present more issues than benefits.

Default Style

• <html>

<head>

<title>

PHP info test page

</title>

</head>

<body>

<?php phpInfo(); ? >

</body>

</html>

• The default syntax for embedding PHP programming units in your web page is the <?php and ?>.

• PHP Program consists of single statement followed by a semicolon.

Delimiting PHP Program Units Conti..

• <html>

<head>

<title>

PHP info test page

</title>

</head>

<body>

<script language=php >

phpInfo();

</script>

</body>

</html>

• PHP also supports a script delimiter.

• The Scripting syntax for embedding PHP programming units in our web pages consists of the<script language=“php”> and </script>.


• <html>

<head>

<title>

PHP info Short-tag test page

</title>

</head>

<body>

<? phpInfo(); ?>

</body>

</html>

• PHP supports short tags provided you enable them in the php.ini configuration file.

• Short tags will have a little advantage and can lead to confusion, if you want to use them, the scripting syntax uses <? And ?>.


• <html>

<head>

<title>

PHP info Short-tag test page

</title>

</head>

<body>

<% phpInfo(); %>

</body>

</html>

• PHP supports Micro ASP page syntax, in order to use the ASP page you need to enable in the php.ini configurations script by editing the asp_tags directive.

• If you want to use them scripting syntax uses <% and % >.

• If you chose to enable asp_tags in your php.ini file, you will need to restart your HTTPD for those changes to take effect.

Displaying Output to Web Pages

• There are two predefined PHP constructs and functions are used to display output to web pages.

• The difference between a function and a construct is that the parentheses are unnecessary in a construct.

• The first constructor is the echo() statement. General syntax for the echo statement is

void echo(string arg1 [, string arg2…])

• The limitation of the echo() constructor is that it returns nothing and therefore cannot be used in complex expression.


• <html>

<head>

<title>

PHP echo() construct test page

</title>

</head>

<body>

<?

echo(“Hello one ! <br>”);

echo “Hello Two! <br>” ; ?>

</body>

</html>

• Each line that uses the echo() construct must be terminated by semicolon, which makes the lines statement of execution.

• In the echo() statement, if you want to pass multiple arguments to the ecjo command parentheses cannot be used.


• There are several escape sequences that may likewise be included in the argument or argument list to the echo() construct.

• <br> is the web browser to perform a line break.

• The /t is the escape sequence for a tab.

• The /n is the escape for a new line.

• The \r is the escape sequence for a carriage return.

• The $ symbol is used to designate variables.

• The backslash is used to back-quote, and double quotes are used to delimit string values.


• The second constructor is the print() statement.

• The benefit of the print() constructor is that it always returns an int value 1. This means that it used in complex expression.

• The difference between the print() and echo() construct is that the print() construct does not support multiple arguments with or without parenthesis.

int print(string arg)


• There are two predefined PHP functions, they are printf() and vprintf().

• The printf() function outputs a formatted string.

printf(format, arg1, arg2, arg++)

• Required. Specifies the string and how to format the variables in it.Possible format values:

• %% - Returns a percent sign

• %b - Binary number

• %c - The character according to the ASCII value

• %d - Signed decimal number (negative, zero or positive)


• %e - Scientific notation using a lowercase (e.g. 1.2e+2)

• %E - Scientific notation using a uppercase (e.g. 1.2E+2)

• %u - Unsigned decimal number (equal to or greather than zero)

• %f - Floating-point number (local settings aware)

• %F - Floating-point number (not local settings aware)

• %g - shorter of %e and %f


• <?php$number = 123;printf("%f",$number);?>

• %G - shorter of %E and %f

• %o - Octal number

• %s - String

• %x - Hexadecimal number (lowercase letters)


• The next function is vprintf() which is similar to printf().

• vprintf() returns a formatted string, Operates as printf() but accepts an array of arguments, rather than a variable number of arguments.

Putting Comments in PHP Programs

• The PHP programming language supports two styles of writing comments.

• Single-Lime Comment: These are used to comment the single line of code by using the forward slashes.

• // , # This is a single line comment

• Multiple-Line Comment: This is used to comment multiple lines of code.

• /* This is a multiple-line comment. */

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Writing Web Pages By Shyam Gurram. Agenda Writing Web Pages Delimiting PHP Program Units. Displaying Output to Web Pages Putting Comments in PHP Programs