JS 切换多窗口

<div style=" text-align:center; margin-top:40px;">
    <div class="menubox">
        <span id="newstab1" class="hover" onmouseover="setTab('newstab',1,3)"> <a href="###" target="_blank">科室新闻</a></span>
        <span id="newstab2" onmouseover="setTab('newstab',2,3)"> <a href="###" target="_blank">媒体报道</a></span>
        <span id="newstab3" onmouseover="setTab('newstab',3,3)"> <a href="###" target="_blank">学术研究</a></span>
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    <div class="contentbox">
        <div id="con_newstab_1">
            <ul>
                <li><span>2015-09-09</span><a href="###" target="_blank">阅谁问君诵水落清香浮1</a></li>
                <li><span>2015-08-17</span><a href="###" target="_blank">阅谁问君诵水落清香浮1</a></li>
                <li><span>2015-08-05</span><a href="###" target="_blank">阅谁问君诵水落清香浮1</a></li>
            </ul>
        </div>
        <div id="con_newstab_2" style="display:none;">
            <ul>
                <li><span>2015-09-09</span><a href="###" target="_blank">阅谁问君诵水落清香浮2</a></li>
                <li><span>2015-08-17</span><a href="###" target="_blank">阅谁问君诵水落清香浮2</a></li>
                <li><span>2015-08-05</span><a href="###" target="_blank">阅谁问君诵水落清香浮2</a></li>
            </ul>
        </div>
        <div id="con_newstab_3" style="display:none;">
            <ul>
                <li><span>2015-09-09</span><a href="###" target="_blank">阅谁问君诵水落清香浮3</a></li>
                <li><span>2015-08-17</span><a href="###" target="_blank">阅谁问君诵水落清香浮3</a></li>
                <li><span>2015-08-05</span><a href="###" target="_blank">阅谁问君诵水落清香浮3</a></li>
            </ul>
        </div>
    </div>
</div>

<script type="text/javascript">
function setTab(name,cursel,n){ 
	for(i=1;i<=n;i++){ 
	var menu=document.getElementById(name+i); 
	var con=document.getElementById("con_"+name+"_"+i); 
	menu.className=i==cursel?"hover":""; 
	con.style.display=i==cursel?"block":"none"; 
	} 
} 
</script>

效果图：