javascript - javascript 计时器到期后显示按钮

Question

如何在 JavaScript 计时器到期后显示按钮？我正在使用 Visual Studio 2010 并基于 ASP 项目进行此操作。

我当前的计时器代码如下:

<script type="text/javascript">
  function countDown(sec, elem) {
  var element = document.getElementById(elem);
  element.innerHTML = "Time left: " + sec + " seconds";
   if (sec < 1) {
    clearTimeout(timer); //clear timeout
    element.innerHTML = 'Time is up!';
    document.getElementById("<%=btnPresentAnswer.ClientID %>").Visible = true;
                }
    sec--;
    var timer = setTimeout('countDown(' + sec + ', "' + elem + '")', 1000);


                }
</script>
<div id="status"></div>
<script type="text/javascript">
    countDown(5, "status");
</script>

Answer 1

也许您应该将 display:none 添加到按钮，然后如果计时器完成，那么您应该将显示值替换为 block 。

示例: 假设你这里有 html block 那么这就是按钮

// html
// head
// end head
// body
       <button style="display:none">Test</button> // this will not show in the UI

       <script>
           // your timer function 
           // then if timer is up you should manipulate the display:none turn it into this display:block;
       </script>
//end body
// end html