onclick事件在表单关闭标记后不起作用

Question

问题是onclick事件按钮在表单开始标记之前（在html文档的开头）可以正常工作但在表单关闭标签后无法使用！我想知道为什么会这样吗？我的按钮位置与js函数调用之间是什么关系？

    <form name="Register" action="#" method="post">
      <fieldset>
        <legend>Personal Information</legend>
      <label>Username</label>
      <input type="text" name="username" placeholder="Enter your name">

      <br><br>

      <label>Password</label>
      <input type="password" name="password" placeholder="Enter your password">

      <br><br>
      <label>Message</label>
      <br>
      <textarea name="message" rows="8" cols="50" readonly>Your Message (currently disabled)</textarea>
      <br><br>

      <label>Upload your cv</label>
      <input type="file" name="cv">

      <br><br>

      <label>Remember me</label>
      <input type="checkbox" name="remember">
      </fieldset>

      <br><br>

      <fieldset>
      <legend>Favourits</legend>
      <label>Choose your browser</label>
      <br>
      <input type="radio" name="browser"> Oprera
      <br>
      <input type="radio" name="browser"> Chrome
      <br>
      <input type="radio" name="browser"> Firefox

      <br><br>

      <label>Choose your Mobile</label>
      <br>
      <input type="radio" name="mobile"> Samsung
      <br>
      <input type="radio" name="mobile"> Apple
      <br>
      <input type="radio" name="mobile"> Nokia
      </fieldset>
      <br><br>

      <fieldset>
      <legend>Button Options</legend>
      <input type="hidden" value="testing">
      <input type="submit" name="submit_Register" value="submit">
      <input type="reset" name="" value="reset">
      </fieldset
    </form>

    <input type="button" name="sayHello" value="sayHello" onclick="sayHello()" />

这是脚本

<script>
      function sayHello()
      {
        alert("Hello");
      }
</script>

Answer 1

由于无效的</fieldset>标签关闭，您的按钮不起作用：

</fieldset

function sayHello()
  {
    alert("Hello");
  }

<input type="button" name="sayHello" value="sayHello" onclick="sayHello()" />
<form name="Register" action="#" method="post">
  <fieldset>
    <legend>Personal Information</legend>
  <label>Username</label>
  <input type="text" name="username" placeholder="Enter your name">

  <br><br>

  <label>Password</label>
  <input type="password" name="password" placeholder="Enter your password">

  <br><br>
  <label>Message</label>
  <br>
  <textarea name="message" rows="8" cols="50" readonly>Your Message (currently disabled)</textarea>
  <br><br>

  <label>Upload your cv</label>
  <input type="file" name="cv">

  <br><br>

  <label>Remember me</label>
  <input type="checkbox" name="remember">
  </fieldset>

  <br><br>

  <fieldset>
  <legend>Favourits</legend>
  <label>Choose your browser</label>
  <br>
  <input type="radio" name="browser"> Oprera
  <br>
  <input type="radio" name="browser"> Chrome
  <br>
  <input type="radio" name="browser"> Firefox

  <br><br>

  <label>Choose your Mobile</label>
  <br>
  <input type="radio" name="mobile"> Samsung
  <br>
  <input type="radio" name="mobile"> Apple
  <br>
  <input type="radio" name="mobile"> Nokia
  </fieldset>
  <br><br>

  <fieldset>
  <legend>Button Options</legend>
  <input type="hidden" value="testing">
  <input type="submit" name="submit_Register" value="submit">
  <input type="reset" name="" value="reset">
  </fieldset>
</form>
<input type="button" name="sayHello" value="sayHello" onclick="sayHello()" />