<html><body><h1>Document 对象</h1><h2>forms 属性</h2><form><p>名字：<input type="text" name="fname" value="Gates"></p><p>姓氏：<input type="text" name="lname" value="Bill"></p></form><p>文档中表单元素的数量是：</p><p id="demo"></p><script>let num = document.forms.length;document.getElementById("demo").innerHTML = num;</script></body></html>