js 防止button频繁点击

 <input type="button" class="test" title="Select" value="Select" />

 <script type="text/javascript">
        $(function () {
            var clicktag = 0;
            $("input.test").click(function () {
                if (clicktag == 0) {
                    clicktag = 1;
                    setTimeout(function () { clicktag = 0 }, 5000);
                }
                else{
                 alert('请勿频繁点击！');
                }
            });
    });
  </script>