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‎19 - Webcam Fun/script.js‎

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Original file line numberDiff line numberDiff line change
@@ -7,46 +7,50 @@ window.onload = function() {
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a = document.querySelector('a');
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//滤色范围记录
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filter = {
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rmin:0,
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rmax:255,
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gmin:0,
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gmax:255,
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bmin:0,
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bmax:255
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rmin: 0,
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rmax: 255,
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gmin: 0,
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gmax: 255,
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bmin: 0,
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bmax: 255
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}
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//调用摄像头数据
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askWebcam();
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askWebcam();
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//绑定change事件动态修改图片颜色
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slider.onchange = function(e) {
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//先将canvas恢复至原始截图
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ctx.putImageData(origindata,0,0);
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ctx.putImageData(origindata, 0, 0);
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const target = e.target;
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//startPos表示操作像素点数据时的起点，从canvas获取到的像素数据每四个值表示一个像素点
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//例如滑块为红色，则只需要改变像素数组中第0,4,8......个元素的值。
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const startPos = {'r':0,'g':1,'b':2}[target.name[0]];
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const startPos = {
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'r': 0,
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'g': 1,
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'b': 2
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}[target.name[0]];
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//filterMin和filterMax表示相应的滤色范围上下限，若修改了红色滤色范围则取红色范围值。
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//若修改蓝色的滤色范围，则取蓝色。
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var tempFilter = checkFilter(target.name, target.value);
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const filterMin = tempFilter.min;
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const filterMax = tempFilter.max;
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//从canvas获取像素数据
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var img = ctx.getImageData(0,0,300,200);
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var img = ctx.getImageData(0, 0, 300, 200);
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var imgd = img.data;
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//色彩过滤
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for(var i=startPos, len = imgd.length; i<len ; i+=4){
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if (imgd[i]< filterMin){
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var imgd = img.data;
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//色彩过滤
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for (var i = startPos, len = imgd.length; i < len; i += 4) {
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if (imgd[i] < filterMin) {
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imgd[i] = filterMin;
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}else if(imgd[i] >filterMax){
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} else if (imgd[i] > filterMax) {
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imgd[i] = filterMax;
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}
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}
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//将修改后的像素数据重绘制至canvas
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ctx.putImageData(img,0,0);
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img.src = canvas.toDataURL();
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}
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//将修改后的像素数据重绘制至canvas
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ctx.putImageData(img, 0, 0);
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img.src = canvas.toDataURL();
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}
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}
@@ -55,7 +59,7 @@ window.onload = function() {
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function takePhoto() {
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ctx.drawImage(video, 0, 0, 300, 200);
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//将原始截图保存
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origindata = ctx.getImageData(0,0,300,200);
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origindata = ctx.getImageData(0, 0, 300, 200);
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}
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//保存图片
@@ -67,7 +71,7 @@ function savePhoto() {
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//申请网络摄像头操作权限
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function askWebcam() {
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navigator.getUserMedia = navigator.getUserMedia ||
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navigator.getUserMedia = navigator.getUserMedia ||
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navigator.webkitGetUserMedia ||
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navigator.mozGetUserMedia;
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if (navigator.getUserMedia) {
@@ -92,17 +96,24 @@ function askWebcam() {
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}
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//滤色函数
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function checkFilter(name, value){
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var _min;
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var _max;
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var _antiname = {'rmin':'rmax','rmax':'rmin','gmin':'gmax','gmax':'gmin','bmin':'bmax','bmax':'bmin'}[name]
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function checkFilter(name, value) {
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var _min;
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var _max;
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var _antiname = {
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'rmin': 'rmax',
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'rmax': 'rmin',
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'gmin': 'gmax',
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'gmax': 'gmin',
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'bmin': 'bmax',
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'bmax': 'bmin'
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}[name]
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filter[name] = value;
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//当下限值超过上限时，将两者对调
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_min = Math.min(filter[name],filter[_antiname]);
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_max = Math.max(filter[name],filter[_antiname]);
112+
_min = Math.min(filter[name], filter[_antiname]);
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_max = Math.max(filter[name], filter[_antiname]);
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console.log(filter);
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return {
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min: _min,
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max: _max
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}
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}
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}

‎22 - Follow Along Link Highlighter/README.md‎

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# 22 Follow Along Link Highliter 中文指南
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> 本篇作者：©[大史快跑Dashrun](https://github.com/dashrun)——Chinasoft Frontend Developer
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> 简介：[JavaScript30](https://javascript30.com) 是 [Wes Bos](https://github.com/wesbos) 推出的一个 30 天挑战。项目免费提供了 30 个视频教程、30 个挑战的起始文档和 30 个挑战解决方案源代码。目的是帮助人们用纯 JavaScript 来写东西，不借助框架和库，也不使用编译器和引用。现在你看到的是这系列指南的第 22 篇。完整指南在 [GitHub](https://github.com/soyaine/JavaScript30)，喜欢请 Star 哦♪(^∇^*)
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> 创建时间：2017-09-12
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最后更新：2017-09-16
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## 挑战任务
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初始文档`index-start.html`提供了一组使用`<ul>`及`<li>`标签包裹的导航标签。本次的编程挑战任务是完成如下动画效果：当鼠标移动至某个对应标签上时，为标签添加一个白色的背景框，高亮表示该标签被选中，当鼠标移动至其他标签后，白色背景框不消失，而是直接跟随鼠标平移至新的标签，实现效果见下图展示。
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## 实现效果
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![结果展示](https://github.com/dashrun/vanilla-javascript-30/blob/master/22%20-%20Follow%20Along%20Link%20Highlighter/effects.gif)
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## 相关知识
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`Element.getBoundingClientRect()`
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Element.getBoundingClientRect()方法返回元素的大小及其相对于视口的位置。
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返回值是一个`DOMRect`对象，这个对象是由该元素的`getClientRects()`方法返回的一组矩形的集合, 即：是与该元素相关的CSS边框集合。`DOMRect` 对象包含了一组用于描述边框的只读属性——left、top、right和bottom，单位为像素。除了 width 和 height 外的属性都是相对于视口的左上角位置而言的。
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DOMRect相关属性:
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Attribute | Type | Description
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--- | --- | ---
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bottom | float | Y 轴，相对于视口原点（viewport origin）矩形盒子的底部。只读。
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height | float | 矩形盒子的高度（等同于 bottom 减 top）。只读。
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left | float | X 轴，相对于视口原点（viewport origin）矩形盒子的左侧。只读。
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right | float | X 轴，相对于视口原点（viewport origin）矩形盒子的右侧。只读。
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top | float | Y 轴，相对于视口原点（viewport origin）矩形盒子的顶部。只读。
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width | float | 矩形盒子的宽度（等同于 right 减 left）。只读。
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x | float | X轴横坐标，矩形盒子左边相对于视口原点（viewport origin）的距离。只读。
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y | float | Y轴纵坐标，矩形盒子顶部相对于视口原点（viewport origin）的距离。只读。
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## 编程思路
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1.生成一个绝对定位的块元素，在后续改变其`top`及`left`坐标值移动至对应标签处，来呈现不同标签被激活的效果;
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2.鼠标移动至`<li>`标签后，使用`Element.getBoundingClientRect()方法`获得该标签的位置信息;
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3.将获得的`<li>`的`top`及`left`值赋给绝对定位块元素，使其移动至被激活的标签，位于标签文字下方。
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## 过程指南
40+
1.生成绝对定位块元素
41+
```js
42+
var activeBackground = document.createElement('span');
43+
activeBackground.setAttribute('class','highlight');
44+
document.body.appendChild(activeBackground);
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46+
//避免第一次激活时跳动,如果没有此句，可以看到第一次标签被激活时，块元素会从左上角移动至对应标签处。
47+
activeBackground.style.display = 'none';
48+
```
49+
2.使用`Element.getBoundingClientRect()方法`获得对应标签的位置信息
50+
```js
51+
function lightOn(e){
52+
var activeLink = e.target.getBoundingClientRect();
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var coords = {
54+
height:activeLink.height,
55+
width:activeLink.width,
56+
left:window.pageXOffset + activeLink.left,
57+
top: window.pageYOffset + activeLink.top
58+
}
59+
activeBackground.style.height = `${coords.height}px`;
60+
activeBackground.style.width = `${coords.width}px`;
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activeBackground.style.left = `${coords.left}px`;
62+
activeBackground.style.top = `${coords.top}px`;
63+
activeBackground.style.display = 'inline';
64+
}
65+
```
66+
3.将点亮函数与标签的鼠标移入事件绑定
67+
```js
68+
//监听鼠标移入事件及鼠标移出事件
69+
for(var i = 0; i < len; i++){
70+
oLi[i].onmouseenter = lightOn;
71+
}
72+
```
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‎22 - Follow Along Link Highlighter/effects.gif‎

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‎22 - Follow Along Link Highlighter/index-finished-Dashrun.html‎

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<!DOCTYPE html>
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<html lang="en">
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<head>
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<meta charset="UTF-8">
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<title>👀👀👀Follow Along Nav</title>
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<link rel="stylesheet" href="style.css">
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</head>
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<body>
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<nav>
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<ul class="menu" id="menu">
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<li><a href="" >Home</a></li>
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<li><a href="">Order Status</a></li>
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<li><a href="">Tweets</a></li>
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<li><a href="">Read Our History</a></li>
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<li><a href="">Contact Us</a></li>
17+
</ul>
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</nav>
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<div class="wrapper">
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<p>Lorem ipsum dolor sit amet, <a href="">consectetur</a> adipisicing elit. Est <a href="">explicabo</a> unde natus necessitatibus esse obcaecati distinctio, aut itaque, qui vitae!</p>
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<p>Aspernatur sapiente quae sint <a href="">soluta</a> modi, atque praesentium laborum pariatur earum <a href="">quaerat</a> cupiditate consequuntur facilis ullam dignissimos, aperiam quam veniam.</p>
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<p>Cum ipsam quod, incidunt sit ex <a href="">tempore</a> placeat maxime <a href="">corrupti</a> possimus <a href="">veritatis</a> ipsum fugit recusandae est doloremque? Hic, <a href="">quibusdam</a>, nulla.</p>
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<p>Esse quibusdam, ad, ducimus cupiditate <a href="">nulla</a>, quae magni odit <a href="">totam</a> ut consequatur eveniet sunt quam provident sapiente dicta neque quod.</p>
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<p>Aliquam <a href="">dicta</a> sequi culpa fugiat <a href="">consequuntur</a> pariatur optio ad minima, maxime <a href="">odio</a>, distinctio magni impedit tempore enim repellendus <a href="">repudiandae</a> quas!</p>
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</div>
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<script>
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var oLi = document.getElementsByTagName('li');
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var len = oLi.length;
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var activeBackground = document.createElement('span');
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activeBackground.setAttribute('class','highlight');
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document.body.appendChild(activeBackground);
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//避免第一次激活时跳动
36+
activeBackground.style.display = 'none';
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//监听鼠标移入事件及鼠标移出事件
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for(var i = 0; i < len; i++){
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oLi[i].onmouseenter = lightOn;
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}
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//鼠标
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function lightOn(e){
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var activeLink = e.target.getBoundingClientRect();
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var coords = {
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height:activeLink.height,
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width:activeLink.width,
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left:window.pageXOffset + activeLink.left,
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top: window.pageYOffset + activeLink.top
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}
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activeBackground.style.height = `${coords.height}px`;
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activeBackground.style.width = `${coords.width}px`;
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activeBackground.style.left = `${coords.left}px`;
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activeBackground.style.top = `${coords.top}px`;
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activeBackground.style.display = 'inline';
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}
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</script>
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</body>
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</html>
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‎22 - Follow Along Link Highlighter/index-start.html‎

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<!DOCTYPE html>
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<html lang="en">
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<head>
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<meta charset="UTF-8">
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<title>👀👀👀Follow Along Nav</title>
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<link rel="stylesheet" href="style.css">
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</head>
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<body>
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<nav>
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<ul class="menu">
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<li><a href="">Home</a></li>
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<li><a href="">Order Status</a></li>
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<li><a href="">Tweets</a></li>
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<li><a href="">Read Our History</a></li>
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<li><a href="">Contact Us</a></li>
17+
</ul>
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</nav>
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<div class="wrapper">
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<p>Lorem ipsum dolor sit amet, <a href="">consectetur</a> adipisicing elit. Est <a href="">explicabo</a> unde natus necessitatibus esse obcaecati distinctio, aut itaque, qui vitae!</p>
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<p>Aspernatur sapiente quae sint <a href="">soluta</a> modi, atque praesentium laborum pariatur earum <a href="">quaerat</a> cupiditate consequuntur facilis ullam dignissimos, aperiam quam veniam.</p>
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<p>Cum ipsam quod, incidunt sit ex <a href="">tempore</a> placeat maxime <a href="">corrupti</a> possimus <a href="">veritatis</a> ipsum fugit recusandae est doloremque? Hic, <a href="">quibusdam</a>, nulla.</p>
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<p>Esse quibusdam, ad, ducimus cupiditate <a href="">nulla</a>, quae magni odit <a href="">totam</a> ut consequatur eveniet sunt quam provident sapiente dicta neque quod.</p>
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<p>Aliquam <a href="">dicta</a> sequi culpa fugiat <a href="">consequuntur</a> pariatur optio ad minima, maxime <a href="">odio</a>, distinctio magni impedit tempore enim repellendus <a href="">repudiandae</a> quas!</p>
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</div>
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<script>
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// 👀👀👀👀👀👀👀👀👀👀👀👀👀👀👀
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</script>
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</body>
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</html>
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‎22 - Follow Along Link Highlighter/style.css‎

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html {
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box-sizing: border-box;
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}
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*, *:before, *:after {
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box-sizing: inherit;
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}
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body {
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min-height: 100vh;
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margin: 0; /* Important! */
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font-family: sans-serif;
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background:
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linear-gradient(45deg, hsla(340, 100%, 55%, 1) 0%, hsla(340, 100%, 55%, 0) 70%),
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linear-gradient(135deg, hsla(225, 95%, 50%, 1) 10%, hsla(225, 95%, 50%, 0) 80%),
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linear-gradient(225deg, hsla(140, 90%, 50%, 1) 10%, hsla(140, 90%, 50%, 0) 80%),
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linear-gradient(315deg, hsla(35, 95%, 55%, 1) 100%, hsla(35, 95%, 55%, 0) 70%);
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}
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.wrapper {
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margin:0 auto;
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max-width:500px;
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font-size: 20px;
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line-height: 2;
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position: relative;
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}
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a {
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text-decoration: none;
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color:black;
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background:rgba(0,0,0,0.05);
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border-radius: 20px
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}
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.highlight {
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transition: all 0.2s;
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border-bottom:2px solid white;
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position: absolute;
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top:0;
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background:white;
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left:0;
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z-index: -1;
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border-radius:20px;
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display: block;
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box-shadow: 0 0 10px rgba(0,0,0,0.2)
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}
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.menu {
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padding: 0;
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display: flex;
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list-style: none;
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justify-content: center;
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margin:100px 0;
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}
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.menu a {
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display: inline-block;
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padding:5px;
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margin:0 20px;
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color:black;
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}

‎README.md‎

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# JavaScript30 - 一个月纯 JS 挑战中文指南
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创建日期：2016-12-20
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最后更新：2017-09-04
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最后更新：2017-09-16
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> Repo by: [缉熙Soyaine](https://github.com/soyaine)
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> [JavaScript30](https://javascript30.com) 教程作者：[Wes Bos](https://github.com/wesbos)
@@ -60,7 +60,7 @@ No | Guide | Demo
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18 | [Adding Up Times with Reduce 指南](https://github.com/soyaine/JavaScript30/tree/master/18%20-%20AddingUpTimesWithReduce) | [使用 Reduce 进行时间叠加效果](https://soyaine.github.io/JavaScript30/18%20-%20AddingUpTimesWithReduce/index-finished-Dashrun-es6.html)
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19 | [Webcam Fun 指南](https://github.com/soyaine/JavaScript30/blob/master/19%20-%20Webcam%20Fun/README.md) | [网络摄像头及图片处理在线效果](https://github.com/soyaine/JavaScript30/blob/master/19%20-%20Webcam%20Fun/index-finished-Dashrun.html)
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20 | [Speech Detection指南](https://github.com/soyaine/JavaScript30/blob/master/20%20-%20Speech%20Detection/README.md) | [Speech Detection效果](https://github.com/soyaine/JavaScript30/blob/master/20%20-%20Speech%20Detection/index-finished-Dashrun.html)
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21 | Geolocation | -
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21 | [Geolocation指南](https://github.com/soyaine/JavaScript30/blob/master/21%20-%20Geolocation/README.md) | [Geolocation效果](https://github.com/soyaine/JavaScript30/blob/master/21%20-%20Geolocation/index-finished-Dashrun.html)
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22 | Follow Along Link Highlighter | -
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23 | Speech Synthesis | -
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24 | Sticky Nav | -
@@ -80,7 +80,7 @@ Name | Contribution
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[@DrakeXiang](https://github.com/DrakeXiang) | No.[11](https://github.com/soyaine/JavaScript30/tree/master/11%20-%20Custom%20Video%20Player)
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[@zzh466](http://github.com/zzh466) | Review
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[@Xing Liu](https://github.com/S1ngS1ng) | Review
83-
[@大史快跑Dashrun](https://github.com/dashrun) | No.[16](https://github.com/soyaine/JavaScript30/tree/master/16%20-%20Mouse%20Move%20Shadow).[17](https://github.com/soyaine/JavaScript30/tree/master/17%20-%20Sort%20Without%20Articles).[18](https://github.com/soyaine/JavaScript30/tree/master/18%20-%20AddingUpTimesWithReduce).[19](https://github.com/soyaine/JavaScript30/blob/master/19%20-%20Webcam%20Fun).[20](https://github.com/soyaine/JavaScript30/tree/master/20%20-%20Speech%20Detection)
83+
[@大史快跑Dashrun](https://github.com/dashrun) | No.[16](https://github.com/soyaine/JavaScript30/tree/master/16%20-%20Mouse%20Move%20Shadow).[17](https://github.com/soyaine/JavaScript30/tree/master/17%20-%20Sort%20Without%20Articles).[18](https://github.com/soyaine/JavaScript30/tree/master/18%20-%20AddingUpTimesWithReduce).[19](https://github.com/soyaine/JavaScript30/blob/master/19%20-%20Webcam%20Fun).[20](https://github.com/soyaine/JavaScript30/tree/master/20%20-%20Speech%20Detection).[21](https://github.com/soyaine/JavaScript30/tree/master/21%20-%20Geolocation)
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