container.appendChild(div);

This line of code appends or adds the div element as a child node to the container element.

The container element could be a HTML element such as a div, section, or article, and it is obtained through document.querySelector or document.getElementById methods.

The div element could be any valid HTML element such as a paragraph, image, or button, and it is created using the document.createElement method.

So, this line of code is used to dynamically create and add new elements to a webpage using JavaScript.

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

这段代码是一个函数，用于创建文字水印的div。下面是每一部分的解释：

function createWatermark(text, color, deg, opacity, count) {

这是函数的定义，它有五个参数：水印的文字、颜色、旋转角度、透明度和数量。

const container = document.createElement("div");
container.className = "watermark";

这里创建一个div元素，并设置了它的class名称为"watermark"。这个div元素用于包含所有的水印元素。

const containerWidth = container.clientWidth;

获取watermark容器的宽度。

const offset = 140;

计算水印的间距。

const totalWidth = count * offset;

计算所有水印元素占据的总宽度。

for (let i = 0; i < count; i++) {

循环count次，创建count个水印元素。

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`;

在循环内部，创建一个div元素作为水印元素，并设置它的文字、颜色、旋转角度、透明度、位置等样式属性。

container.appendChild(watermark);

将每个水印元素添加到watermark容器中。

return container;

返回watermark容器，即所有水印元素的父元素。