​x
 
<!DOCTYPE html>
<html>
<body>
​
<input type="file" id="myFile" autofocus>
​
<p>单击“尝试”按钮可查看文件上传按钮是否在页面加载时自动获得焦点。</p>
​
<p id="demo"></p>
​
<button onclick="myFunction()">试一试</button>
​
<script>
function myFunction() {
  var x = document.getElementById("myFile").autofocus;
  document.getElementById("demo").innerHTML = x;
}
</script>
​
</body>
</html>
​