Javascript对象/数组循环和创建表问题

// 遍历数组
var arr = [1, 2, 3];
for (var i = 0; i < arr.length; i++) {
  console.log(arr[i]);
}

// 遍历对象
var obj = { name: 'John', age: 30 };
for (var key in obj) {
  console.log(key + ': ' + obj[key]);
}

var arr = [1, 2, 3];
arr.forEach(function(element) {
  console.log(element);
});

var arr = [1, 2, 3];
var newArr = arr.map(function(element) {
  return element * 2;
});
console.log(newArr);

// 创建表格
var table = document.createElement('table');

// 创建表头
var thead = document.createElement('thead');
var tr = document.createElement('tr');
var th1 = document.createElement('th');
th1.textContent = 'Name';
var th2 = document.createElement('th');
th2.textContent = 'Age';
tr.appendChild(th1);
tr.appendChild(th2);
thead.appendChild(tr);
table.appendChild(thead);

// 创建表格内容
var tbody = document.createElement('tbody');
var data = [
  { name: 'John', age: 30 },
  { name: 'Jane', age: 25 },
  { name: 'Bob', age: 35 }
];
data.forEach(function(item) {
  var tr = document.createElement('tr');
  var td1 = document.createElement('td');
  td1.textContent = item.name;
  var td2 = document.createElement('td');
  td2.textContent = item.age;
  tr.appendChild(td1);
  tr.appendChild(td2);
  tbody.appendChild(tr);
});
table.appendChild(tbody);

// 将表格添加到页面中
document.body.appendChild(table);