id = name

This attribute assigns a name to an element. This name must be unique in a document.

class = cdata-list

This attribute assigns a class name or set of class names to an element. Any number of elements may be assigned the same class name or names. Multiple class names must be separated by white space characters.

我理解你的问题的精神是通过有意选择唯一的类名,你可以模拟id属性给出的功能,可以说使id属性变得多余.好吧,我能想到至少有一件事只能用ids来做;关联< label>带有for属性的表单元素的元素.例如：

<label for="firstname">First Name:<label>
<input type="text" id="firstname" name="firstname" value="" />

出于可访问性原因,这是一种很好的做法.如果您使用< label for =“id”>使用复选框或单选按钮元素,您可以获得可点击标签的额外奖励.例如：

<label for="male">Male</label> <!-- the word "Male" is clickable -->
<input type="radio" id="male" name="sex" value="male" />
<label for="female">Female</label> <!-- the word "Female" is clickable -->
<input type="radio" id="female" name="sex" value="female" />