jq选择器 http://www.runoob.com/
$("p:not(.intro)").css("background-color","blue"); //p标签除了class=“intro”外的颜色....
与 $("p:visible").css("background-color","yellow")<选取所有可见的元素>;用法相反
1)<input type="text" name="user" />
2)<input type="password" name="password" disabled="disabled" />
3)<select multiple="multiple">
<option>Volvo</option>
<option selected="selected">Saab</option>
<option>Mercedes</option>
<option>Audi</option>
</select>
4)<input type="radio" name="sex" value="male" checked="checked"/>