简单了解
requestAnimationFrame
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<title>Page Title</title>
<meta name="viewport" content="width=device-width, initial-scale=1" />
<style type="text/css">
#box {
margin: 0 auto;
height: 100px;
background: green;
margin-top: 100px;
}
</style>
</head>
<body>
<div id="box">123</div>
<script>
let index = 0;
const callback = () => {
index += 1;
console.log(123);
document.querySelector("#box").style.width = index + "px";
document.querySelector("#box").innerHTML = index;
if (index < 300) {
requestAnimationFrame(callback);
} else {
cancelAnimationFrame(xxx);
alert(1);
}
};
const xxx = requestAnimationFrame(callback);
</script>
</body>
</html>
WebWorker
main.html
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
<style>
div {
display: flex;
}
input {
width: 200px;
height: 50px;
font-size: 30px;
}
button {
width: 100px;
height: 50px;
}
button:last-child {
width: 200px;
}
.mess {
font-size: 30px;
}
</style>
</head>
<body>
<div>
<input type="text" title="" id="msg" maxlength="5" />
<button onclick="sendMessage()">发送</button>
<button onclick="stopWorker()">关闭worker线程</button>
</div>
<span class="mess"></span>
<script type="text/javascript">
if (typeof Worker === "undefined")
document.writeln(" Sorry! No Web Worker support.. ");
else {
// 主线程中创建worker子线程
// 参数一: 脚本网址(同源js脚本) 参数二:配置对象
const worker = new Worker("workerThread1.js", {
name: "Fhup",
});
worker.onmessage = (ev) => {
document.querySelector(".mess").innerHTML = ev.data;
};
worker.onerror = (error) => {
worker.terminate();
// 发生错误的文件名、行号、错误内容
console.log(error.filename, error.lineno, error.message);
};
function sendMessage() {
const msg = document.getElementById("msg");
worker.postMessage(msg.value);
}
function stopWorker() {
worker.terminate();
}
}
</script>
</body>
</html>
workerThread1.js
// Worker线程: 全局对象为 self,代表子线程自身,这时 this指向self
console.log(self.name); // 配置值
self.onmessage = (ev) => {
let info = ev.data;
info = "==>" + info + "<==";
self.postMessage(info);
};
注意: 如果报错相似,请使用vscode的live server运行
使用场景
// 主线程
let w = new Worker("js/workers.js");
w.onmessage = function (event) {
var img = document.createElement("img");
img.src = window.URL.createObjectURL(event.data);
document.querySelector("#result").appendChild(img);
};
// worker线程
let arr = [...好多图片路径];
for (let i = 0, len = arr.length; i < len; i++) {
let req = new XMLHttpRequest();
req.open("GET", arr[i], true);
req.responseType = "blob";
req.setRequestHeader("client_type", "DESKTOP_WEB");
req.onreadystatechange = () => {
if (req.readyState == 4) {
postMessage(req.response);
}
};
req.send(null);
}
