auto close bootstrap alerts

bootstrap.alerts.close.js

(function () {
    var timeout = 0;
    $('.alert').each(function () {
        var
            $alert = $(this),
            text = $alert.text().replace(/(^\s+|\s+$)/, ''),
            num_lines = $alert.height() / parseFloat($alert.css('line-height')),
            num_words = text.split(/\s{2,}/).length,
        // 120 words per minute and add a second for each line.
            seconds = (num_words / 120 * 60) + num_lines;

        timeout += (seconds * 1000);
        setTimeout(function () {
            $alert.alert('close');
        }, timeout);
    });
})();