方法一:
通过隐藏域获取
<%String userName = session.getAttribute("userName").toString();%>
<input type="hidden" name="userName" id="userName" value="<%=userName%>">
<script type="text/javascript">
var name=document.getElementById("userName").value;
</script>
方法二:
直接获取
<%String userName = session.getAttribute("userName").toString();%>
<script type="text/javascript">
var name=“<%=userName%>”;
</script>