Javascript。如何在页面加载后调用此函数（简单计时器）？

Question

如何在页面加载后调用此函数（简单计时器）？我真的需要您就最简单的方法提出建议。

<script>
  //Timer function
function timer(tag, sec) {
  document.getElementById(tag).innerHTML = "<div id= 'inTime'>" +
      (sec / 60 >> 0) + 'min ' + sec % 60 + 'sec' + '<br>' + "</div>";



    if ((sec / 60 >> 0) != 0 || (sec % 60) != 0) {
      setTimeout(function() {
        timer(tag, sec);
      }, 1000);
      sec -= 1;
    } else {
      document.getElementById(tag).innerHTML = "Time is over!";
    }
  }
</script>

<div id="timerPlace"></div>
<br>
<br>
<br>
<br>
<!-- Write number of seconds here: onclick="timer('str',...here!...)  -->

<button class="button" onclick="timer('timerPlace',3600); style.display = 'none'"> <span>Start Test</span> 
</button> 

<!-- Place this div where you whant timer to be. -->

Answer 1

你的问题不是很清楚，但如果我明白你的意思，你需要使用window.onload=function(){ /*code here*/ }，代码将在页面加载后立即执行。

<script>
  //Timer function
function timer(tag, sec) {
  document.getElementById(tag).innerHTML = "<div id= 'inTime'>" +
      (sec / 60 >> 0) + 'min ' + sec % 60 + 'sec' + '<br>' + "</div>";



    if ((sec / 60 >> 0) != 0 || (sec % 60) != 0) {
      setTimeout(function() {
        timer(tag, sec);
      }, 1000);
      sec -= 1;
    } else {
      document.getElementById(tag).innerHTML = "Time is over!";
    }
  }
window.onload=function(){
timer('timerPlace',3600);
}
</script>

<div id="timerPlace"></div>
<br>
<br>
<br>
<br>
<!-- Write number of seconds here: onclick="timer('str',...here!...)  -->

<button class="button" onclick="timer('timerPlace',3600); style.display = 'none'"> <span>Start Test</span> 
</button> 

<!-- Place this div where you whant timer to be. -->