AJAX - PHP
- Conventional web applications transmit information to and from the server using synchronous requests. It means you fill out a form, hit submit, and get directed to a new page with new information from the server.
The following example will demonstrate how a web page can communicate with a web server while a user types characters in an input field:
In the example above, when a user types a character in the input field, a function called "showing()" is executed.
The onkeyup event triggers the function.
Here is the HTML code:
First, check if the input field is empty (str.length == 0). If it is, clear the content of the txtHint placeholder and exit the function.
Do the following, if the input field is not empty:
- Create an XMLHttpRequest object
- Create the function to be executed when the server response is ready
- Send the request off to a PHP file (gethint.php) on the server
- Notice that the q parameter is added to the url (gethint.php?q="+str)
- And the str variable holds the content of the input field
The PHP File - "gethint.php."
The PHP file checks an array of names, and returns the corresponding name(s) to the browser: