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>