tryjsref_number_form 在线代码实例

 <form id="myForm">
<input type="number" id="myNumber" value="2">
</form>
<p>点击按钮返回 number 字段所属的表单id。</p>
<button onclick="myFunction()">点我</button>
<p id="demo"></p>
<script>
function myFunction() {
    var x = document.getElementById("myNumber").form.id;
    document.getElementById("demo").innerHTML = x;
}
</script>