dunjudge time sorting

// ==UserScript==
// @name         dunjudge time sorting
// @namespace    dunjudgeTimeSort
// @version      1.0
// @description  Sorting submissions by time
// @author       Element118
// @match        https://dunjudge.me/analysis/problems/*/
// @grant        none
// ==/UserScript==

(function() {
    'use strict';
    let xhttp = new XMLHttpRequest();
    let href = window.location.href.split("/");
    let problemID = href[href.length-2];
    let userID = document.getElementsByClassName("btn btn-default btn-flat")[0].href;
    userID = userID.substring("https://dunjudge.me/users/".length, userID.length-1);
    let subTable = (function() {
        let pastSub = document.getElementsByClassName("box box-")[0];
        let box = document.createElement("div"); box.className = "box box-success";
        let header = document.createElement("div"); header.className = "box-header";
        let headerText = document.createElement("h3"); headerText.className = "box-title"; headerText.textContent = "Submissions by Time";
        header.appendChild(headerText);
        box.appendChild(header);
        let boxBody = document.createElement("div");
        // display: none; to hide
        boxBody.className = "box-body no-padding scrollbar"; boxBody.style="height: 200px; overflow: auto; display: block;"; boxBody.id="ac_time_subbox";
        let boxTable = document.createElement("table");
        boxTable.className = "table table-bordered center table-hover"; boxTable.id = "ac_time_subs";
        boxTable.innerHTML = "<thead><tr><th>Rank</th><th>subID</th><th>User</th><th>Time</th><th>Max Time</th></tr></thead>";
        let boxTableBody = document.createElement("tbody");
        boxTable.appendChild(boxTableBody);
        boxBody.appendChild(boxTable);
        box.appendChild(boxBody);
        pastSub.parentNode.insertBefore(box, pastSub);
        return boxTableBody;
    })();
    let addData = function(data) {
        subTable.innerHTML += '<tr><td>'+data.rank+'</td><td><a href="/analysis/submissions/'+data.subID+'/">'+data.subID+'</a></td><td><a href="/users/'+data.userID+'/">'+data.userID+'</a></td><td>'+data.subTime+'</td><td>'+data.maxTime+'</td></tr>';
    };
    let submissions = [];
    let currentSub = 1000000000;
    xhttp.onreadystatechange = function() {
        if (this.readyState == 4 && this.status == 200) {
            let newData = JSON.parse(xhttp.responseText).moresub;
            submissions = submissions.concat(newData);
            if (newData.length > 0) {
                currentSub = newData[newData.length-1].subID;
                xhttp.open("GET", "https://dunjudge.me/ui/submissions_list.php?query_type=accepted&problemID="+problemID+"&botsub="+currentSub+"&lastupd=0", true);
                xhttp.send();
            } else {
                let hashTable = {}; // name -> subid, time
                for (let i=0;i<submissions.length;i++) {
                    // <td><a href='/analysis/submissions/SUB_ID/'>SUB_ID</a></td><td><a href='/users/USER_ID/'>USER_ID</a></td><td>SUB_TIME</td><td>MAX_TIME</td>
                    let subID = submissions[i].subID;
                    let tokens = submissions[i].str.split("<td>"); // assuming <td> doesn't appear anywhere else
                    // 0: [empty string]
                    // 1: <a href='/analysis/submissions/SUB_ID/'>SUB_ID</a></td>
                    // 2: <a href='/users/USER_ID/'>USER_ID</a></td>
                    // 3: SUB_TIME</td>
                    // 4: MAX_TIME</td>
                    let userID = tokens[2].substring(tokens[2].indexOf(">")+1); // SUB_ID</a></td>
                    userID = userID.substring(0, userID.indexOf("<")); // SUB_ID
                    let subTime = tokens[3].substring(0, tokens[3].indexOf("<")); // SUB_TIME
                    let maxTime = +tokens[4].substring(0, tokens[4].indexOf("<")); // MAX_TIME
                    if (!hashTable[userID] || hashTable[userID].maxTime > maxTime) {
                        hashTable[userID] = {
                            subID: subID,
                            userID: userID,
                            subTime: subTime,
                            maxTime: maxTime,
                            rank: 0
                        };
                    }
                }
                let sortedSubs = [];
                for (let i in hashTable) {
                    sortedSubs.push(hashTable[i]);
                }
                sortedSubs.sort(function(a, b) {
                    if (a.maxTime !== b.maxTime) return a.maxTime - b.maxTime;
                    return (+a.subID) - (+b.subID);
                });
                let prevRank = 0, prevTime = -1, userPosition = 0;
                for (let i=0;i<sortedSubs.length;i++) {
                    if (sortedSubs[i].maxTime > prevTime) {
                        prevRank = i+1;
                        prevTime = sortedSubs[i].maxTime;
                    }
                    sortedSubs[i].rank = prevRank;
                    // unused?
                    if (sortedSubs[i].userID == userID) {
                        userPosition = i;
                    }
                    addData(sortedSubs[i]);
                }
            }
        }
    };
    xhttp.open("GET", "https://dunjudge.me/ui/submissions_list.php?query_type=accepted&problemID="+problemID+"&botsub="+currentSub+"&lastupd=0", true);
    xhttp.send();
})();