JavaScript 按名称获取元素 [英] JavaScript get element by name

问题描述

考虑这个函数:

function validate()
{
  var acc = document.getElementsByName('acc').value;
  var pass = document.getElementsByName('pass').value;

  alert (acc);
}

还有这个 HTML 部分:

And this HTML part:

<table border="0" cellpadding="2" cellspacing="0" valign="top">
    <tr>
        <td class="td1">Account</td>
        <td class="td2"><input type="text" name="acc" /></td>
    </tr>
    <tr class="td1">
        <td>Password</td>
        <td class="td2"><input type="password" name="pass" /></td>
    </tr>
</table>
<div><button onClick="validate()" class="cupid-greenx">Login now</button></div>

警告框正在显示，但显示未定义".

The alert box is showing, but it shows "undefined".

推荐答案

您看到该错误的原因是 document.getElementsByName 返回一个 NodeList 元素.并且元素的 NodeList 没有 .value 属性.

The reason you're seeing that error is because document.getElementsByName returns a NodeList of elements. And a NodeList of elements does not have a .value property.

改用这个:

document.getElementsByName("acc")[0].value

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