sms-counter.html

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title>SMS counter test (JS)</title>
        <script src="https://code.jquery.com/jquery-2.1.4.min.js"></script>
    </head>
    <body>
        <textarea style="width:400px;height:200px;"></textarea>
        <div id="answer">0</div>
        <script>
        $(document).ready(function () {
            /*
             * Compute the number of characters and SMS needed to send a message.
             */
            function smsCharCount(message) {
                var gsm7bitChars   = "@£$¥èéùìòÇ\nØø\rÅåΔ_ΦΓΛΩΠΨΣΘΞÆæßÉ !\"#¤%&'()*+,-./0123456789:;<=>?¡ABCDEFGHIJKLMNOPQRSTUVWXYZÄÖÑÜ§¿abcdefghijklmnopqrstuvwxyzäöñüà";
                var gsm7bitExChars = "^{}\\[~]|€";

                // default to GSM-7bit, we'll detect if we need to switch to
                // UCS-2 later.
                var data = {
                    encoding: 'GSM-7bit',
                    characters: 0,
                    max_chars_for_one_sms:   160,
                    max_chars_for_many_sms:  153
                };

                // This JS loop is UTF-8 (input) aware.
                for (var i = 0, len = message.length; i < len; i++) {
                    var c = message.charAt(i);
                    if (gsm7bitChars.indexOf(c) > -1) {
                        data.characters += 1;
                    } else if (gsm7bitExChars.indexOf(c) > -1) {
                        data.characters += 2;
                    } else {
                        // we're reading a character that cannot be
                        // represented in the GSM-7bit charset, switch to
                        // UCS-2.
                        data.encoding = 'UCS-2';
                        data.characters = message.length;
                        data.max_chars_for_one_sms  = 70;
                        data.max_chars_for_many_sms = 67;
                        break;
                    }
                }

                // compute the number of SMS needed.
                if (data.characters <= data.max_chars_for_one_sms) {
                    // simple case, only one SMS.
                    data.sms = 1;
                    data.remaining = data.max_chars_for_one_sms - data.characters;
                } else {
                    // use SMS concatenation
                    data.sms       = 1 + Math.floor((data.characters - 1) / data.max_chars_for_many_sms);
                    data.remaining = (data.sms * data.max_chars_for_many_sms) - data.characters;
                }

                return data;
            }

            // textarea tester.
            $('textarea').keyup(function () {
                var data = smsCharCount($(this).val());
                var txt = data.sms + " SMS encoded in " + data.encoding;
                txt    += " (" + (data.sms == 1 ? data.max_chars_for_one_sms : data.max_chars_for_many_sms) + " character per SMS).<br>";
                txt    += data.characters + " characters in total, " + data.remaining + " character left until next SMS.";
                $('#answer').html(txt);
            });
        });
        </script>
    </body>
</html>