浏览器

01、实现全屏当您需要将当前屏幕显示为全屏时

function fullScreen() {  
    const el = document.documentElement
    const rfs = 
    el.requestFullScreen || 
    el.webkitRequestFullScreen || 
    el.mozRequestFullScreen || 
    el.msRequestFullscreen
    if(typeof rfs != "undefined" && rfs) {
        rfs.call(el)
    }
}
fullScreen()

02、退出全屏

当您需要退出全屏时

function exitScreen() {
    if (document.exitFullscreen) { 
        document.exitFullscreen()
    } 
    else if (document.mozCancelFullScreen) { 
        document.mozCancelFullScreen()
    } 
    else if (document.webkitCancelFullScreen) { 
        document.webkitCancelFullScreen()
    } 
    else if (document.msExitFullscreen) { 
        document.msExitFullscreen()
    } 
    if(typeof cfs != "undefined" && cfs) {
        cfs.call(el)
    }
}
exitScreen()

03、页面打印

当您需要打印当前页面时

window.print()

04、打印内容风格变更

当需要打印出当前页面，但需要修改当前布局时

print
noprint

05、阻止关闭事件

当需要阻止用户刷新或关闭浏览器时，可以选择触发beforeunload事件，有些浏览器无法自定义文本内容

window.onbeforeunload = function(){
    return 'Are you sure you want to leave the haorooms blog？';
};

06、屏幕录制

当您需要录制当前屏幕并上传或下载屏幕录制时

const streamPromise = navigator.mediaDevices.getDisplayMedia()
streamPromise.then(stream => {
    var recordedChunks = [];// recorded video data
var options = { mimeType: "video/webm; codecs=vp9" };// Set the encoding format
    var mediaRecorder = new MediaRecorder(stream, options);// Initialize the MediaRecorder instance
    mediaRecorder.ondataavailable = handleDataAvailable;// Set the callback when data is available (end of screen recording)
    mediaRecorder.start();
    // Video Fragmentation
    function handleDataAvailable(event) {
        if (event.data.size > 0) {
            recordedChunks.push(event.data);// Add data, event.data is a BLOB object
            download();// Encapsulate into a BLOB object and download
        }
    }
// file download
    function download() {
        var blob = new Blob(recordedChunks, {
            type: "video/webm"
        });
        // Videos can be uploaded to the backend here
        var url = URL.createObjectURL(blob);
        var a = document.createElement("a");
        document.body.appendChild(a);
        a.style = "display: none";
        a.href = url;
        a.download = "test.webm";
        a.click();
        window.URL.revokeObjectURL(url);
    }
})

07、判断横屏和竖屏

当您需要判断手机横屏或竖屏状态时

const streamPromise = navigator.mediaDevices.getDisplayMedia()
streamPromise.then(stream => {
    var recordedChunks = [];// recorded video data
var options = { mimeType: "video/webm; codecs=vp9" };// Set the encoding format
    var mediaRecorder = new MediaRecorder(stream, options);// Initialize the MediaRecorder instance
    mediaRecorder.ondataavailable = handleDataAvailable;// Set the callback when data is available (end of screen recording)
    mediaRecorder.start();
    // Video Fragmentation
    function handleDataAvailable(event) {
        if (event.data.size > 0) {
            recordedChunks.push(event.data);// Add data, event.data is a BLOB object
            download();// Encapsulate into a BLOB object and download
        }
    }
// file download
    function download() {
        var blob = new Blob(recordedChunks, {
            type: "video/webm"
        });
        // Videos can be uploaded to the backend here
        var url = URL.createObjectURL(blob);
        var a = document.createElement("a");
        document.body.appendChild(a);
        a.style = "display: none";
        a.href = url;
        a.download = "test.webm";
        a.click();
        window.URL.revokeObjectURL(url);
    }
})

08、改变横竖屏样式

当你需要为横竖屏设置不同的样式时

09、标签页隐藏

当需要监听tab显示和隐藏事件时

const {hidden, visibilityChange} = (() => {
    let hidden, visibilityChange;
    if (typeof document.hidden !== "undefined") {
      // Opera 12.10 and Firefox 18 and later support
      hidden = "hidden";
      visibilityChange = "visibilitychange";
    } else if (typeof document.msHidden !== "undefined") {
      hidden = "msHidden";
      visibilityChange = "msvisibilitychange";
    } else if (typeof document.webkitHidden !== "undefined") {
      hidden = "webkitHidden";
      visibilityChange = "webkitvisibilitychange";
    }
    return {
      hidden,
      visibilityChange
    }
})();

const handleVisibilityChange = () => {
    console.log("currently hidden", document[hidden]);
};
document.addEventListener(
    visibilityChange,
    handleVisibilityChange,
    false
);

图片

10、本地图片预览

当您从客户端获取图片但无法立即上传到服务器，但需要预览时

11、图片预加载

当图片较多时，需要预加载图片以避免白屏

const images = []
function preloader(args) {
    for (let i = 0, len = args.length; i < len; i++) {  
        images[i] = new Image()  
        images[i].src = args[i]
    } 
}  
preloader(['1.png', '2.jpg'])

JavaScript

12、字符串脚本

当需要将一串字符串转换为JavaScript脚本时，该方法存在xss漏洞，请谨慎使用

const obj = eval('({ name: "jack" })')
// obj will be converted to object{ name: "jack" }
const v = eval('obj')
// v will become the variable obj

13、递归函数名解耦

当需要编写递归函数时，声明了函数名，但是每次修改函数名时，总是忘记修改内部函数名。argument是函数的内部对象，包括传入函数的所有参数，arguments.callee代表函数名。

// This is a basic Fibonacci sequence
function fibonacci (n) {
    const fn = arguments.callee
    if (n <= 1) return 1
    return fn(n - 1) + fn(n - 2)
}

DOM 元素

14、隐性判断

当需要判断某个dom元素当前是否出现在页面视图中时，可以尝试使用IntersectionObserver来判断。

  
Invisible
  
Invisible
  
Invisible

15、元素可编辑

当你需要编辑一个dom元素时，让它像文本区域一样点击。

here can be edited

16、元素属性监控

test
OK

17、打印 dom 元素

当开发过程中需要打印dom元素时，使用console.log往往只能打印出整个dom元素，而无法查看dom元素的内部属性。你可以尝试使用 console.dir

console.dir(document.body)

其他

18、激活应用程序

当你在移动端开发时，你需要打开其他应用程序。还可以通过location.href赋值来操作以下方法

phone
android message 
ios message
ios message

总结

以上就是我今天想与你分享的全部内容，希望对你有所帮助，最后，感谢你的阅读，祝编程愉快!