AJAX is used to create more interactive applications.
AJAX PHP Example
The following example will demonstrate how a web page can communicate with a web server while a user type characters in an input field:
In the example above, when a user types a character in the input field, a function called “showHint()” is executed.
The function is triggered by the onkeyup event.
Here is the HTML code:
Start typing a name in the input field below:
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.
However, if the input field is not empty, do the following:
- 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 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: