利用JavaScript和CSS实现输入分钟、秒倒计时功能

<p class="container-fluid"> 
 <p class="main-content-inner"> 
 <p class="page-content">
  <p class="page-header"> 
  <form class="form-inline" id="searchform"> 
  <p class="form-group" style="margin-left: 10px;">
   <label>分</label> 
  <input type="text" class="form-control" name="Minute" id="Minute">
   </p> 
  <p class="form-group" style="margin-left: 10px;"> 
  <label>秒</label> 
  <input type="text" class="form-control" name="Second" id="Second">
   </p>
  <button type="button" class="btn btn-purple btn-sm" onclick="ok()"> 开始 </button> 
  </form>
  </p>
  <p class="row" style="height:500px;line-height:500px;vertical-align:middle;font-size:200px;color:red;text-align:center;margin-top:100px"> <p id="listview"></p> 
  </p> 
 </p>
  </p> 
 </p>

 <script>
  var t;
  var Minute;
  var Second; 
  var d;
  function ok() {
   if ($("#Minute").val() == "0" || $("#Minute").val() == "") {
   Minute = 0;
   } else {
   Minute = $("#Minute").val();
   }
   if ($("#Second").val() == "0" || $("#Second").val() == "") {
   Second = 0;
   } else {
   Second = $("#Second").val();
   }
  var min = "";
  if (Minute < 10) {
   min = "0" + Minute;
  } else {
   min = Minute + "";
  }
  var sec = "";
  if (Second < 10) {
   sec = "0" + Second;
  } else {
   sec = Second + "";
  }
  $("#listview").text(min + ":" + sec);
  $(".page-header").hide();
  $("#listview").show();
  setTimeout(function () {
   begin()
  }, 1000);  
  }
  function begin() {  
  if (Second != 0) {
   Second--;
   min = "";
   if (Minute < 10) {
   min = "0" + Minute;
   } else {
   min = Minute + "";
   }
   sec = "";
   if (Second < 10) {
   sec = "0" + Second;
   } else {
   sec = Second + "";
   }
   $("#listview").text(min + ":" + sec);
  } else {
   if (Minute > 0) {
   Minute--;
   Second = 59;
   min = "";
   if (Minute < 10) {
    min = "0" + Minute;
   } else {
    min = Minute + "";
   }
   sec = "";
   if (Second < 10) {
    sec = "0" + Second;
   } else {
    sec = Second + "";
   }
   $("#listview").text(min + ":" + sec);
   } else {
   clearTimeout(t);
   }
  }
  t = setTimeout(function () {
   begin()
  }, 1000)
  }
 </script>