html
<div id="PersonalInfoLeft" >
<div id="P0" class="eeedss1">
<span class="Icocss"> </span>
<div >
<span class="TextLeftcss">合同</span>
</div>
</div>
<div id="P1" class="eeedss1">
<span class="Icocss"> </span>
<div >
<span class="TextLeftcss">任务书</span>
</div>
</div>
<div id="P2" class="eeedss1" style="margin-bottom:0px;">
<div>
<span class="Icocss"> </span>
<span class="TextLeftcss" >工作大纲</span>
</div>
</div>
<div id="P3" class="eeedss1">
<span class="Icocss"> </span>
<div>
<span class="TextLeftcss">设计</span>
</div>
</div>
</div>
js jquery
$("#PersonalInfoLeft").children("div").eq(0).attr("class","eeedss");这个有效
$("div[id^='P']").eq(0).attr("class","eeedss");这个就乱套了
$("div[id^='P':eq(0)]").attr("class","eeedss");//也是乱套的
但是
$("div[id^='P']").hide(); 这个是OK的
神马原因呢 先搁着 有时间去查查 干项目去了