Basic Php

Using PHP for Web applicationsIn the beginning, Web pages were static - they just presented documents.Users went to Web sites to read information. Documents were linked togetherso that users could easily find the information they sought, but the Web pagesdidn't change. Every user who arrived at a Web page saw the same thing.Soon Web page developers wanted to do more. They wanted to interact withvisitors, collect information from users, and provide Web pages that werecustomized for individuals. Several languages have developed that can beused to make Web sites dynamic. PHP is one of the most successful of theselanguages, evolving quickly to become more and more useful and rapidlygrowing in popularity.PHP is a server-side scripting language, which means that the scripts are executedon the  server (the computer where the Web site is located). This is different

Because PHP scripts execute on the server, PHP can dynamically create the HTML code that generates the Web page, which allows individual users to see customized Web pages. Web page visitors see the output from scripts, but not the scripts themselves. PHP has many features designed specifically for use in Web sites, including the following: Interact with HTML forms: PHP can display an HTML form and process the information that the user types in. Communicate with databases: PHP can interact with databases to store information from the user or retrieve information that is displayed to the user. Generate secure Web pages: PHP allows the developer to create secure Web pages that require users to enter a valid username and password before seeing the Web page content. PHP features make these and many other Web page tasks easy. PHP is only server-side, meaning it can't interact directly with the user's computer. That means PHP can't initiate actions based on the status of the user's computer, such as mouse actions or screen size. Therefore, PHP alone can't produce some popular effects, such as navigation menus that drop down or change color. On the other hand, JavaScript, a client-side scripting language.