javascript - 关于循环结束后获取不到点击事件想要的对象-PHP中文网问答

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title></title>
        <style>
            body,html {margin: 0;padding: 0;}
            nav {width: 100px;height: 25px;border: 1px solid rosybrown;color: #fff;float: left;text-align: center;line-height: 25px;}
        </style>
    <script type="text/javascript">
    window.onload = function() {
        var arr = [{
            title: "科技",
            bgcolor: "blue",
            currentbg: "block",
            hash: "keji"
        }, {
            title: "军事",
            bgcolor: "blue",
            currentbg: "yellow",
            hash: "junshi"
        }, {
            title: "新闻",
            bgcolor: "blue",
            currentbg: "red",
            hash: "xinwen"
        }];
        var adom = [];
        for (var attr in arr) {
            if (!arr.hasOwnProperty(attr) || ("title" in arr[attr] && arr[attr]["title"] !== "")) {
                var oNav = document.createElement("nav");
                oNav.innerHTML = arr[attr]["title"];
                oNav.style.backgroundColor = arr[attr]["bgcolor"];
                oNav.setAttribute("data-hash", arr[attr]["hash"]);
                document.querySelector("body").appendChild(oNav);
                adom.push(oNav);
                oNav.onclick = function() {
                    var hash = this.dataset.hash; //获取hash
                    window.location.hash = hash; //传给url
                    for (var j in adom) {
                        adom[j].style.backgroundColor = arr[j]["bgcolor"];
                    }
                    //我这里想获取当前选中状态下他对应的背景颜色在arr下的currentbg下
                    //比如我当前选中状态是第2个nav对应的就是this.style.backgroundColor="yellow"
                    this.style.backgroundColor = ;
                };
                window.onhashchange = function() { //url发现改变页面跟着变
                    hashchange();
                }
                hashchange();

                function hashchange() {
                    var firstHash = window.location.hash.substring(1) || "";
                    for (var key in arr) {
                        document.querySelector("." + arr[key]["hash"]).style.display = "none";
                    }
                    if (firstHash) {
                        document.querySelector("." + firstHash).style.display = "block";
                    }
                };
            }
        }
    }
</script>
    </head>
    <body>
        <p data-hash="keji" class="keji">科技版块</p>
        <p data-hash="junshi" class="junshi" style="display: none;">军事版块</p>
        <p data-hash="xinwen" class="xinwen" style="display: none;">新闻版块</p>
    </body>
</html>

oNav.onclick = function(oldAttr){ return function() { var hash = this.dataset.hash; //获取hash window.location.hash = hash; //传给url for (var j in adom) { adom[j].style.backgroundColor = arr[j]["bgcolor"]; } //我这里想获取当前选中状态下他对应的背景颜色在arr下的currentbg下 //比如我当前选中状态是第2个nav对应的就是this.style.backgroundColor="yellow" this.style.backgroundColor = oldAttr.currentbg; }; }(arr[attr]);