<p class="p">This is a paragraph</p><!-- 类选择符 --> <div class="p">This is a div element</div><!-- 类选择符 --> <p class="urgent warning">This is a paragraph</p><!-- 多类选择符，一个class可以包含一个词列表，各个词之间用空格隔开 --> <p class="urgent warning help">Those words's background-color is red too in all browser!</p><!-- 多类选择符，.waring.urgent选择器将不能匹配这里的p --> <p class=" help ie6">Those words's background-color is red in browser ie6!</p><!-- 多类选择符，由于help在选择器中最后出现，所以在IE6中背景为红色的 --> <p class="help">Those words's background-color is red in browser ie6!</p><!-- 类选择符，由于help在选择器中最后出现，所以在IE6中背景为红色的 --> <p>This is a paragraph<span class="warning"> But this is a span element</span></p>
