x
 
<!DOCTYPE html>
<html>
<body>
<h1>演示如何访问提交按钮</h1>
<input type="submit" id="mySubmit" value="提交表单">
<p>单击“试一试”按钮可获取提交按钮上显示的文本。</p>
<button onclick="myFunction()">试一试</button>
<p id="demo"></p>
<script>
function myFunction() {
  var x = document.getElementById("mySubmit").value;
  document.getElementById("demo").innerHTML = x;
}
</script>
</body>
</html>