这段前端代码有一个显示题目的区域，一个文本框用来用户回答的答案，还有一个提交按钮，点击提交按钮后显示题目答案，并校对用户答案，题库db中题目t有四个属性为id,timu,answer,biaoji,当校对后的题目前端的answer=t.answer时t.biaoji=0否则t.biaoji=1,之后在前端点击一个按钮为"我的错题集"可以查看t.biaoji=1的题目，那么前端和后端的代码是什么

前端代码示例：

HTML部分：

<div>
  <h2 id="question"></h2>
  <input type="text" id="answer" placeholder="请输入答案">
  <button id="submitBtn">提交</button>
</div>
<div>
  <button id="errorBtn">我的错题集</button>
</div>

JavaScript部分：

//题目数组，应该从后端获取
let questionArr = [
  {id: 1, timu: "1+1=?", answer: "2", biaoji: 0},
  {id: 2, timu: "2+2=?", answer: "4", biaoji: 0},
  {id: 3, timu: "3+3=?", answer: "6", biaoji: 0},
];

let questionIndex = 0; //当前题目下标

//显示题目
function showQuestion() {
  let curQuestion = questionArr[questionIndex];
  document.getElementById("question").innerText = curQuestion.timu;
}

//提交答案
function submitAnswer() {
  let curQuestion = questionArr[questionIndex];
  let userAnswer = document.getElementById("answer").value;
  if (userAnswer === curQuestion.answer) {
    curQuestion.biaoji = 0;
    alert("恭喜你，回答正确！");
  } else {
    curQuestion.biaoji = 1;
    alert("很遗憾，回答错误！");
  }
}

//显示错题集
function showError() {
  let errorArr = questionArr.filter(q => q.biaoji === 1);
  let errorStr = errorArr.map(q => q.timu + "，答案：" + q.answer).join("\n");
  alert(errorStr);
}

//绑定按钮事件
document.getElementById("submitBtn").addEventListener("click", submitAnswer);
document.getElementById("errorBtn").addEventListener("click", showError);

//初始化
showQuestion();

后端代码示例：

from flask import Flask, jsonify, request

app = Flask(__name__)

# 题目数组
questionArr = [
    {"id": 1, "timu": "1+1=?", "answer": "2", "biaoji": 0},
    {"id": 2, "timu": "2+2=?", "answer": "4", "biaoji": 0},
    {"id": 3, "timu": "3+3=?", "answer": "6", "biaoji": 0},
]

# 显示题目
@app.route("/showQuestion")
def showQuestion():
    global questionArr
    curQuestion = questionArr[0]
    return jsonify({"id": curQuestion["id"], "timu": curQuestion["timu"]})

# 提交答案
@app.route("/submitAnswer", methods=["POST"])
def submitAnswer():
    global questionArr
    curQuestion = questionArr[0]
    userAnswer = request.form.get("answer")
    if userAnswer == curQuestion["answer"]:
        curQuestion["biaoji"] = 0
        return jsonify({"result": "恭喜你，回答正确！"})
    else:
        curQuestion["biaoji"] = 1
        return jsonify({"result": "很遗憾，回答错误！"})

# 显示错题集
@app.route("/showError")
def showError():
    global questionArr
    errorArr = [q for q in questionArr if q["biaoji"] == 1]
    errorStr = "\n".join([q["timu"] + "，答案：" + q["answer"] for q in errorArr])
    return errorStr

if __name__ == "__main__":
    app.run()

这里只是提供一个简单的示例，实际情况下需要根据具体需求进行修改和完善。