创建与 INPUT type=text 控件类似的单行文本输入控件，不过并不显示用户输入的内容。
Creates a single-line text entry control similar to the INPUT type=text control, except that text is not displayed as the user enters it.
此元素在 Internet Explorer 3.0 及以上版本的 HTML 和脚本中可用。
此元素是一个内嵌元素。
此元素不需要关闭标签。
The INPUT type=password element is available in HTML and script as of Internet Explorer 3.0.
This element is an inline element.
This element does not require a closing tag.
<input type="password" name="yourpw">