*{ margin:0px auto; padding:0px}
#xiala{ width:180px; height:33px; border:1px solid #999;text-align:center; line-height:33px; vertical-align:middle; }
#xiala:hover{ cursor:pointer}

#zi{width:180px; height:150px; border:1px solid #63C; border-top:0px; display:none}

.list{width:180px; height:33px; text-align:center; line-height:33px; vertical-align:middle; border-bottom:1px solid #63C; background-color:#CCC}
.list:hover{ cursor:pointer; background-color:#63C; color:white}

<div style="width:700px; height:500px; margin-top:30px">

    <div id="xiala" onclick="Show()"></div>    
    <div id="zi">
        <div class="list" onclick="Xuan(this)">山东</div>
        <div class="list" onclick="Xuan(this)">淄博</div>
        <div class="list" onclick="Xuan(this)">张店</div>
    </div>
</div>

function Show()
{
    document.getElementById("zi").style.display="block";
}
function Xuan(ys)
{
    var v = ys.innerText;
    
    document.getElementById("xiala").innerText = v;
    
    document.getElementById("zi").style.display="none";
}