PHP Programming and Application_PHP Tutorial

Chapter 1 Introduction to PHP3

PHP is a server-built-in script language. Its emergence makes it possible to quickly develop dynamic web on Unix.
PHP was conceived by Rasmus Lerdorf in the fall of 1994. The earliest unreleased version was on his homepage that he used to keep in touch with people viewing his online resume. The first version delivered to users was released in early 1995, and it was only used as a personal homepage creation tool. At that time it only included a very simple analysis engine that understood only a few macros and a set of tools for homepage information feedback (a guestbook, a counter and a few other things). In mid-1995, Rasmus rewrote the entire parser and named it PHP/FI 2. FI comes from another software package he wrote for html form integration data. He merged the personal homepage tool and the form integration tool together, and added mSQL database support, so there was PHP/FI. Since then, PHP/FI has spread at an amazing speed, and people have begun to use it to write programs.
We are unable to accurately estimate its usage scope, but it is estimated that by the end of 1996, at least 15,000 sites in the world were using PHP/FIl. By mid-1997 this number had grown to over 50,000 sites. In mid-1997 we also discovered a major turning point in the development of PHP. This is how the development of PHP has been upgraded from Rasmus's personal hobby to the organized work of a group of programmers. Later, this parser was rewritten by Zeev Suraski and Andi Gutmans. Through this comprehensive rewrite, a large number of PHP/FI functions were transplanted into PHP3 and became the basic prototype of PHP3.
By mid-1998, there were already a large number of commercial products, such as C2's StrongHold web server and RedHat Linux bundled with PHP/FI parser or PHP3 parser. According to conservative data estimated by NetCraft, PHP has been used by the world Used by over 150,000 sites. Through further analysis, we know that the number of its uses is far greater than the number of sites using Netscape's flagship product, the enterprise-class WEB server. PHP3 extensively adopts the syntax of C, Java and Perl languages, and adds various PHP own features. One difference between it and JavaScript and other languages ​​is that PHP3 is executed on the server, and what the client sees is the result of running it on the server. This means that if you want to use PHP3 scrpit, you must have WEB SERVER support.
PHP3 supports HTTP authentication, cookies, and GIF image creation. One of its most representative features is its database layer, which makes it very simple to write database-based web pages. The following lists the currently supported databases:
Oracle, Sybase, mSQL, MySQL, Informix, Solid dBase, ODBC, Unix dbm, PostgreSQL, Adabas D, FilePro Velocis.

PHP3 also supports network programming with services using POP3, HTTP, SNMP, NNTP, IMAP and other protocols.
PHP3 program mode

There are three ways to enter "PHP program mode" from HTML:
The first method: PHP3 statement; ?>


For example:
echo("this is the simplest, an SGML processing instructionn"); ?>



The second method:

For example:



First Method: