what is encoding in Ajax?

Question

Generally we are using UTF-8 encoding standard for sending the request for every language. But in some language this encoding standard is not working properly,then in that case we are using ISO-8859-1.

Answer 1

This is a rather vague question.

If you mean to ask, "what is encoding in AJAX?" then the answer is that AJAX is not an encoding, it is a method of client-server communication.

If you meant to ask, "what encoding does AJAX use?" then the answer is that AJAX responses can use whatever encoding you want, but it should typically match the encoding of the HTML page that made the request.

Answer 2

You can use any encoding you want. However from your question, it sounds like typically you're using UTF-8, but sometimes you're getting data from somewhere that's coming in with a different encoding (eg, Internet Explorer tends to like send data to the web server using ISO-8859-1).

If you're going to serve up UTF-8 encoded text, and you get non-UTF-8 encoded text from somewhere, you have to convert that to UTF-8 before you send it down the line. Probably a good practice is to automatically sanitize all data received from the web browser and re-encode it as UTF-8. Unfortunately the browser doesn't always tell you what encoding it's using; if it's not supplied you can probably assume it's UTF-8 or ISO-8859-1.

If you're using a server side language, you're going to want to look into how to convert encodings with that language. For example, PHP has iconv() function calls, and a very nice function mb_detect_encoding($text) which will do a pretty decent job of guessing what the encoding is for a given bit of data when you don't already know.

Something like this would be in order (presuming PHP serverside):

$text = iconv(mb_detect_encoding($text), 'UTF-8', $text);

Do this with all user input before you do anything else with it (eg, use array_map to automatically convert user inputs):

function convert_to_utf8($text) {
    return iconv(mb_detect_encoding($text), 'UTF-8', $text);
}
$_GET = array_map('convert_to_utf8', $_GET);
$_POST = array_map('convert_to_utf8', $_POST);

Best yet would be to determine if the browser is supplying an encoding, and use that as the first argument to iconv() instead of mb_detect_encoding.