container.appendChild(div);

This line of code adds the 'div' element as a child of the 'container' element.

The 'appendChild' method is a built-in method in JavaScript that allows you to add a new child node to an existing parent node. In this case, the 'div' element is being added to the 'container' element, which means that it will be placed inside the 'container' element in the HTML document.

This is a common technique used in web development to dynamically add new content to a web page using JavaScript. By adding new elements as children of existing elements, you can create more complex and dynamic web pages that respond to user interactions and other events.

相关问题

function generate() { var redBalls = []; while (redBalls.length < 6){ var num = Math.floor(Math.random() * 33) + 1; if (redBalls.indexOf(num) === -1) { redBalls.push(num); } } redBalls.sort(function(a,b){ return a - b; }); var blueBall = Math.floor(Math.random() * 16) + 1; var result = redBalls.map(num => (num < 10 ? '0' + num : num.toString())).join(" ") + " " + (blueBall < 10 ? '0' + blueBall : blueBall.toString()); displayResult(result); } function displayResult(result){ var container = document.getElementById("ball-container"); container.innerHTML = ""; for (var i = 0; i <6; i++) { var ball = document.createElement("div"); ball.classList.add("red-ball"); ball.innerHTML = result.split(" ")[i]; container.appendChild(ball); } var ball = document.createElement("div"); ball.classList.add("blue-ball"); ball.innerHTML = result.split(' ')[6]; container.appendChild(ball); } 更改代码为jQuery

以下是使用 jQuery 改写后的代码：

function generate() {
  var redBalls = [];
  while (redBalls.length < 6){
    var num = Math.floor(Math.random() * 33) + 1;
    if (redBalls.indexOf(num) === -1) {
      redBalls.push(num);
    }
  }
  redBalls.sort(function(a,b){
    return a - b;
  });
  var blueBall = Math.floor(Math.random() * 16) + 1;
  var result = redBalls.map(num => (num < 10 ? '0' + num : num.toString())).join(" ") + " " + (blueBall < 10 ? '0' + blueBall : blueBall.toString());
  displayResult(result);
}

function displayResult(result){
  var $container = $("#ball-container");
  $container.empty();
  for (var i = 0; i <6; i++) {
    var $ball = $("<div>").addClass("red-ball").text(result.split(" ")[i]);
    $container.append($ball);
  }
  var $ball = $("<div>").addClass("blue-ball").text(result.split(' ')[6]);
  $container.append($ball);
}

其中，`document.getElementById` 改为了 `$()`，`innerHTML` 改为了 `text()`，`document.createElement` 改为了 `$("<div>")`，`classList` 改为了 `addClass()`，`appendChild` 改为了 `append()`，`container.innerHTML = ""` 改为了 `$container.empty()`。

/** * 创建一个文字水印的div * @param {string} text - 水印文字 * @param {string} color - 水印颜色 * @param {number} deg - 水印旋转角度 * @param {number} opacity - 水印透明度 * @param {number} count - 水印数量 */function createWatermark(text, color, deg, opacity, count) { // 创建水印容器 const container = document.createElement("div"); container.className = "watermark"; // TODO: 根据输入参数创建文字水印 // 获取水印的宽度 const containerWidth = container.clientWidth; // 计算间距 const offset = 140; // 计算总宽度 const totalWidth = count * offset; for (let i = 0; i < count; i++) { // 创建水印元素 const watermark = document.createElement("div"); watermark.textContent = text; watermark.style.color = color; watermark.style.transform = `rotate(${deg}deg)`; watermark.style.opacity = opacity; watermark.style.pointerEvents = 'none'; watermark.style.position = "absolute"; watermark.style.userSelect = "none"; watermark.style.top = "250px"; watermark.style.left = `${(containerWidth - totalWidth) / 2 + i * offset}px`; // 添加水印到容器中 container.appendChild(watermark); } // 返回水印容器 return container;}解释每串代码的意思

该代码是创建一个文字水印的函数，具体解释如下：

function createWatermark(text, color, deg, opacity, count) {
  // 创建水印容器
  const container = document.createElement("div");
  container.className = "watermark";

  // 获取水印的宽度
  const containerWidth = container.clientWidth;

  // 计算间距
  const offset = 140;

  // 计算总宽度
  const totalWidth = count * offset;

  // 循环创建指定数量的水印元素
  for (let i = 0; i < count; i++) {
    // 创建水印元素
    const watermark = document.createElement("div");
    watermark.textContent = text;
    watermark.style.color = color;
    watermark.style.transform = `rotate(${deg}deg)`;
    watermark.style.opacity = opacity;
    watermark.style.pointerEvents = 'none';
    watermark.style.position = "absolute";
    watermark.style.userSelect = "none";
    watermark.style.top = "250px";
    watermark.style.left = `${(containerWidth - totalWidth) / 2 + i * offset}px`;

    // 添加水印到容器中
    container.appendChild(watermark);
  }

  // 返回水印容器
  return container;
}

具体解释如下：

1. `function createWatermark(text, color, deg, opacity, count)`：定义一个名为`createWatermark`的函数，它接受五个参数：水印文字，水印颜色，水印旋转角度，水印透明度和水印数量。

2. `const container = document.createElement("div"); container.className = "watermark";`：创建一个`div`元素，并将其类名设置为`watermark`，作为容器用于存放水印元素。

3. `const containerWidth = container.clientWidth;`：获取容器的宽度。

4. `const offset = 140;`：定义水印元素之间的间距。

5. `const totalWidth = count * offset;`：计算出所有水印元素所占据的总宽度。

6. `for (let i = 0; i < count; i++) {...}`：循环创建指定数量的水印元素。

7. `const watermark = document.createElement("div");`：创建一个`div`元素，用于存放水印文字。

8. `watermark.textContent = text;`：设置水印文字。

9. `watermark.style.color = color;`：设置水印文字的颜色。

10. `watermark.style.transform = `rotate(${deg}deg)`;`：设置水印文字的旋转角度。

11. `watermark.style.opacity = opacity;`：设置水印文字的透明度。

12. `watermark.style.pointerEvents = 'none';`：设置水印文字不响应鼠标事件。

13. `watermark.style.position = "absolute";`：设置水印文字的定位方式为绝对定位。

14. `watermark.style.userSelect = "none";`：设置水印文字不能被选中。

15. `watermark.style.top = "250px";`：设置水印文字距离容器顶部的距离。

16. `watermark.style.left = `${(containerWidth - totalWidth) / 2 + i * offset}px`;`：设置水印文字距离容器左侧的距离。

17. `container.appendChild(watermark);`：将水印元素添加到容器中。

18. `return container;`：返回水印容器。