javascript链接高亮显示的简洁代码

    var theObj;
    function hoverIt(obj) {
        if (theObj != null) {
            theObj.style.background = "#fff";
        }
        if (theObj = obj) {
            obj.style.background = "red";
        }
    }

<div>
    <span onclick="hoverIt(this)">菜单一</span>
    <span onclick="hoverIt(this)">菜单二</span>
    <span onclick="hoverIt(this)">菜单三</span>
    <span onclick="hoverIt(this)">菜单四</span>
</div>