为什么把class里的online换成id里的callme，图标就变了？？

              <div class="login-state-txt" id="login2qq_state_txt">在线</div>

       <ul id="loginStatePanel" class="statePanel login-state" style="display: none">

        <li id="online" class="statePanel_li">

            <div class="stateSelect_icon online"></div>

            <div class="stateSelect_text">我在线上</div>

        </li>

        <li id="callme" class="statePanel_li">

            <div class="stateSelect_icon callme"></div>

            <div class="stateSelect_text">Q我吧</div>

        </li>