仿微博字数提示小插件

本来是自己写了一个的，然后发现这个的扩展性比我写的要方便，所以就借花献佛啦~~原出自找不到了
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script type="text/javascript" src="http://www.liehuo.net/uploads/common/js/jquery-1.4.2.min.js"></script>
<script type="text/javascript">
(function ($) {
    // tipWrap:  提示消息的容器
    // maxNumber:  最大输入字符
    $.fn.artTxtCount = function (tipWrap, maxNumber) {
        var countClass = 'js_txtCount',
            // 定义内部容器的CSS类名
            fullClass = 'js_txtFull',
            // 定义超出字符的CSS类名
            disabledClass = 'disabled'; // 定义不可用提交按钮CSS类名
        // 统计字数
        var count = function () {
                var btn = $(this).closest('form').find(':submit'),
                    val = $(this).val().length,
                    // 是否禁用提交按钮
                    disabled = {
                        on: function () {
                            btn.removeAttr('disabled').removeClass(disabledClass);
                        },
                        off: function () {
                            btn.attr('disabled', 'disabled').addClass(disabledClass);
                        }
                    };
                if (val == 0) disabled.off();
                if (val <= maxNumber) {
                    if (val > 0) disabled.on();
                    tipWrap.html('<span class="' + countClass + '">\u8FD8\u80FD\u8F93\u5165 <strong>' + (maxNumber - val) + '</strong> \u4E2A\u5B57</span>');
                } else {
                    disabled.off();
                    tipWrap.html('<span class="' + countClass + ' ' + fullClass + '">\u5DF2\u7ECF\u8D85\u51FA <strong>' + (val - maxNumber) + '</strong> \u4E2A\u5B57</span>');
                };
            };
        $(this).bind('keyup change', count);
        return this;
    };
})(jQuery);

// demo
jQuery(function(){
// 批量
$('.autoTxtCount').each(function(){
$(this).find('.text').artTxtCount($(this).find('.tips'), 140);
});
// 单个
$('#test').artTxtCount($('#test_tips'), 10);
});
</script>
<style>
/* demo */
body {
	font-size:75%;
	font-family:'微软雅黑';
}
#demo {
	500px;
}
#demo .help, #demo .help a {
	color:#999;
}
#demo form {
	margin:20px 0;
	padding:8px;
	background:#F4F4F4;
	border:1px solid #EDEDED;
}
#demo .tips {
	color:#999;
	padding:0 5px;
}
#demo .tips strong {
	color:#1E9300;
}
#demo .tips .js_txtFull strong {
	color:#F00;
}
#demo textarea.text {
	474px;
}
</style>
</head>
<body>
<div id="demo">
  <h1>artTxtCount - 轻量级输入字数提示插件</h1>
  <p class="help">$('#text').artTxtCount($('#text_tips'), 10);</p>
  <p class="help">by tangbin. <a href="http://www.liehuo.net" target="_blank" title="planeArt">www.liehuo.net</a></p>
  <form class="autoTxtCount" action="" method="get">
    <div>
      <textarea class="text" name="" cols="50" rows="3"></textarea>
    </div>
    <div>
      <button type="submit">提交</button>
      <span class="tips"></span> </div>
  </form>
  <form class="autoTxtCount" action="" method="get">
    <div>
      <textarea class="text" name="" cols="50" rows="3"></textarea>
    </div>
    <div>
      <button type="submit">提交</button>
      <span class="tips"></span> </div>
  </form>
  jQuery文本框实时显示可输入字数并可禁止输入提示超出，强！
  <form action="" method="get">
    <input class="text" id="test" name="" type="text" />
    <span id="test_tips" class="tips"></span><br />
    <button type="submit">提交</button>
  </form>
</div>
</body>
</html>