/**
* Display interactive character limit feedback for text field or text area.
* see http://ndpsoftware.com/show_char_limit.php
*/
jQuery.fn.show_char_limit = function(limit, opts) {

    if (!opts.status_element && !opts.status_element_suffix) {
        throw new Exception("Must provide status_element or status_element_suffix");
    }

    var o = jQuery.extend({
        error_class: 'error',
        status_style: 'text'
    }, opts);

    var show_limit = function(src) {
        var chars_typed = jQuery(src).val().length;
        var left = limit - chars_typed;
        var msg;
        if (o.status_style == 'chars_typed') {
            msg = "" + chars_typed;
        } else if (o.status_style == 'chars_left') {
            msg = "" + left;
        } else {
            var status = left >= 0 ? 'left' : 'over';
            var unit = (Math.abs(left) != 1 ? "characters" : "character");
            msg = "" + Math.abs(left) + " " + unit + " " + status;
        }
        var e = o.status_element ? o.status_element : ("#" + jQuery(src).attr('id') + o.status_element_suffix);
        jQuery(e).html(msg);
        if (o.error_element || o.error_element_suffix) {
            var e = o.error_element ? o.error_element : ("#" + jQuery(src).attr('id') + o.error_element_suffix);
            if (left < 0) {
                jQuery(e).addClass(o.error_class);
            } else {
                jQuery(e).removeClass(o.error_class);
            }
        }
    };

    return this.each(function() {
        show_limit(this);
        jQuery(this).keyup(function() {
            show_limit(this);
        });
    });
};