//オプショナルチェーン (optional chaining) 演算子 (?.)👍
let email = data?.email;

localStorage.getItem("bgcolor_code")

localStorage.setItem("bgcolor_code",color)

<link rel="stylesheet" href="examplestyle.css">

<span id="site_description"></span>

let htmlcode = ["#efefef", "#181B39", "#262a2e", "#192734", "#1c483b", "#bf7800", "#83094f"].map(elm => `<span class='color_code' style='color:${elm}' data-color-code='${elm}'>■</span>`).join("\n");

const basecolor = "#262a2e";
let cookiefn = function (CodeColor) {
    let r = document.cookie.split(';');
    return r.length ? ((r) => {
        let changecolor = "";
        for (let ii = 0; ii < r.length; ii++) {
            let content = r[ii].split('=');
            for (let i = 0; i < content.length; i++) {
                if (content[i].replaceAll(" ", "") === "bgcolor_code") {
                    changecolor = content[i + 1];
                }
            }
        }
        return changecolor?changecolor:CodeColor;
    })(r) : CodeColor;
};

let old_color = cookiefn(basecolor);
document.getElementById("site_description").insertAdjacentHTML("afterend", htmlcode);
[...document.querySelectorAll(".color_code")].forEach(elm => {
    elm.addEventListener("click", function (e) {
        color_set(elm.getAttribute("data-color-code"));
    });
});

color_set(old_color);

function color_set(color) {
    for (let ii = 0; ii < document.styleSheets.length; ii++) {
        if (String(document.styleSheets[ii].href).match(/mag_tcd036-child\/style\.css\?ver=/)) {
            for (let i = 0; i < document.styleSheets[ii].cssRules.length; i++) {
                let element_css_code = document.styleSheets[ii].cssRules[i];
                try {
                    element_css_code.style.backgroundColor = color;
                    if (color === "#efefef") {
                        element_css_code.style.color = "#000000";
                        
                    } else {
                        element_css_code.style.color = "#FFFFFF";
                    }
//いらないかも領域🤔👇
                    document.querySelectorAll("#wp-calendar > tbody > tr > td > a").forEach(elm=>{
                        elm.style.backgroundColor = "#909091";
                    });
                    document.getElementById("searchsubmit").style.backgroundColor = "#000";
                    document.querySelector("#s").style.backgroundColor = "#909091";
                    [...document.querySelectorAll("code")].forEach(elm=>{
                        [...elm.querySelectorAll("span")].forEach(childen_elm=>{
                            childen_elm.style.backgroundColor = "#565656";
                        });
                    });
//いらないかも領域🤔👆                    
                } catch (error) {
                }
            }

            document.cookie = "bgcolor_code=" + color;
        }
    }
}

function imagesDrive() {
  //画像を仕分けフォルダID googleドライブURL->adaoiujxzouaunWxz33oam__ （ランダム英数字記号の部分）
  const folder = DriveApp.getFolderById('画像を仕分けフォルダID'); 
 //移動先のフォルダID googleドライブURL-> UQIJjaoskamlqaxalp98swq--e （ランダム英数字記号の部分）
  const imgfolder = DriveApp.getFolderById('移動先のフォルダID');
  let hasfiles = folder.getFiles();
  while(hasfiles.hasNext()){
    let hasfile = hasfiles.next();
    if(/(\.png|\.jpg)$/.test(hasfile.getName())){
      hasfile.moveTo(imgfolder);
    }
  }
}

function imagesDrive() {
  //画像を仕分けフォルダID googleドライブURL->adaoiujxzouaunWxz33oam__ （ランダム英数字記号の部分）
  const folder = DriveApp.getFolderById('画像を仕分けフォルダID'); 
 //移動先のフォルダID googleドライブURL-> UQIJjaoskamlqaxalp98swq--e （ランダム英数字記号の部分）
  let folderId = {png:'移動先のフォルダID1',jpg:"移動先のフォルダID2",gif:"移動先のフォルダID3"};
  Object.keys(folderId).forEach((keyname)=>{
    let imgfolder = DriveApp.getFolderById(folderId[keyname]);
    let hasfiles = folder.getFiles();
    while(hasfiles.hasNext()){
      let hasfile = hasfiles.next();
      let r = new RegExp("(\."+ keyname + ")$");
      if(r.test(hasfile.getName())){
        hasfile.moveTo(imgfolder);
      }
    }
  });
}

        function moji(o) {
            let m = o.nextElementSibling;
            //ads
            let h = ((o) => {
                let l = o.value.match(/(https?:\/\/[a-z|A-Z|0-9|\-|_|%|\.|\/]{0,})/giu);
                let ml = l ? ((l) => {
                    return sum = l.reduce((s, e) => {
                        return s + e.length;
                    }, 0);
                })(l) : 0;
                return l ? {
                    len: (l.length * 23),
                    mlen: ml
                } : {
                    len: 0,
                    mlen: ml
                };
            })(o);
            //zenkaku            
            let k = ((o) => {
                let l = o.value.match(/[^\x20-\x7e]/giu);
                let ml = l ? ((l) => {
                    return sum = l.reduce((s, e) => {
                        return s + e.length;
                    }, 0);
                })(l) : 0;
                return l ? {
                    len: (l.length * 2),
                    mlen: l.length
                } : {
                    len: 0,
                    mlen: ml
                };
            })(o);
            m.innerHTML = "【 " + (o.value.length + h.len - h.mlen + k.len - k.mlen) + "文字{半角/280} 】";
            if ((o.value.length + h.len - h.mlen + k.len - k.mlen) >= 280) {
                m.innerHTML = "<span class='text-danger'>【 " + (o.value.length + h.len - h.mlen + k.len - k.mlen) + "文字{半角/280} 】</span>";
            }
        }

                    <label for="my-textarea" class="h3">文字を入力してください。</label>
                    <textarea id="my-textarea" class="form-control" oninput="moji(this);" name="" rows="3"></textarea>
                    <span class="h3"></span>

document.getElementById("sh").addEventListener("input",(e)=>{
    $.ajax({
        type: "post",
        url: "example.com/sh.php",
        data: {text:this.value},
        dataType: "json",
        success: function (response) {
            
        }
    });
});

fetch(next_url).then(
                response => response.text()
            ).then(data => {

                const parser = new DOMParser();
                const doc = parser.parseFromString(data, 'text/html');

let cnt = 2;
let blk = 0;
async function nextpage() {
    if (cnt !== blk) {
        blk = cnt;
        await (async () => {
            let next_url = "https://fox-black.com/blog/page/" + cnt;
            return await fetch(next_url).then(
                response => response.text()
            ).then(data => {
                const parser = new DOMParser();
                const doc = parser.parseFromString(data, 'text/html');
                let blogs = doc.querySelectorAll('.blogpage');
                cnt++;
                if (blogs[0].innerHTML !== undefined) {
                    document.querySelector(".foxpage").insertAdjacentHTML("beforeend", (function (elm) {
                        let str = "";
                        for (const key in elm) {
                            const element = elm[key];
                            if (element.innerHTML !== undefined) {
                                str += "<div class=\"blogpage\">" + element.innerHTML + "</div>";
                            }
                        }
                        return str;
                    })(blogs));
                } else {
                    if (document.querySelector("#fin") === null) {
                        document.querySelector(".foxpage").insertAdjacentHTML("beforeend", "<div id=\"fin\"></div>");
                    }
                }
            }).catch(error => {
                if (document.querySelector("#fin") === null) {
                    document.querySelector(".foxpage").insertAdjacentHTML("beforeend", "<div id=\"fin\"></div>");
                }
            });
        })();
    }
}

if (navigator.userAgent.match(/iPhone|Android.+Mobile/)) {
    window.addEventListener("scroll", async function () {
        let s = (() => {
            let tgt;
            if ('scrollingElement' in document) {
                tgt = document.scrollingElement;
            } else if (this.browser.isWebKit) {
                tgt = document.body;
            } else {
                tgt = document.documentElement;
            }
            return tgt;
        })();
        if (document.querySelector("#fin") === null && s.scrollTop >= (s.clientHeight - 650)) {
            await nextpage();
        }
    });
} else {
    document.querySelector(".foxpage").addEventListener("scroll", async function () {
        if (document.querySelector("#fin") === null && document.querySelector(".foxpage").scrollTop >= (document.querySelector(".foxpage").scrollHeight - 300)) {
            await nextpage();
        }
    });
}

    <form id="frm" method="post" action="./example/">
        <input type="hidden" name="example" value="data">
        <button type="submit" class="btn btn-primary">Submit1</button>
    </form>
    <form method="post" action="./example/">
        <input type="hidden" name="example" value="data">
        <button id="btn" type="submit" class="btn btn-primary">Submit2</button>
    </form>    
    <form method="post" action="./example/" onsubmit="return func1()" >
        <input type="hidden" name="example" value="data">
        <button type="submit" class="btn btn-primary">Submit3</button>
    </form>
    <form method="post" action="./example/"  >
        <input type="hidden" name="example" value="data">
        <button type="submit" class="btn btn-primary" onclick="return func2()" >Submit4</button>
    </form>

//例１
document.getElementById("frm").addEventListener("submit",function(event){
    event.preventDefault();
});
//例２
document.getElementById("btn").addEventListener("click",function(event){
    event.preventDefault();
    event.stopPropagation();//インターフェイスのメソッドで、キャプチャおよびバブリング段階において現在のイベントのさらなる伝播を阻止します。 
});
//例３
function func1(){
    return false;
}
//例４
function func2(){
    return false;
}

var showDiffDate = function( tYear, tMonth, tDay) {
    var nowDate = new Date();
    var dnumNow = nowDate.getTime();
    var targetDate = new Date( tYear, tMonth-1, tDay );
    var dnumTarget = targetDate.getTime();

    var diffMSec = dnumTarget - dnumNow;
    var diffDays = diffMSec / ( 1000 * 60 * 60 * 24 );
    var showDays = Math.ceil( diffDays ); 
    var Msg;
    if( showDays >= 0 ) {
       Msg = "" + showDays + " days(" + function(){
         var is_days = parseInt(parseInt(showDays) - Math.floor(showDays / 7) * 2);
         is_days = (nowDate.getDay() === 0)?is_days -2:is_days;
         is_days = (nowDate.getDay() === 6)?is_days -3:is_days;
         return is_days;
       }() +")";
    }
    else {
       Msg = "" + (showDays * -1) + "";
    }
    return Msg;
 };

 document.getElementById("days").innerText = showDiffDate(2022,7,15);

"use strict";
const main = (a,b,c)=>{
    return new Promise ((resolve)=>{
        console.log(a,b,c);
        b++;
        resolve({a:a,b:b,c:c}); 
    });
}
(async()=>{
    await main("A1",1,"C1").then((val)=>main(val.a,val.b,val.c)).then((val)=>main(val.a,val.b,val.c)).then((val)=>main(val.a,val.b,val.c));
    // main("A1",1,"C1").then((val)=>main(val.a,val.b,val.c)).then((val)=>main(val.a,val.b,val.c)).then((val)=>main(val.a,val.b,val.c));
    console.log("fin");
})();

"use strict";
var csv = {
	load:async function(filename,id){
		const responseFile = await fetch(filename);
        const result = await responseFile.text()
		let separate1 = /\r\n/;
		let separate2 = ",";
		let data = (result.split(separate1)).map(function(value){
			return (value.split(separate2)).map(function(value1){
				return value1;
			});
		});
		let sum =[];
		for (const usedata of data) {
            (usedata).map(function(val,index,array){
                sum[index] = (isNaN(parseInt(sum[index]))?0:parseInt(sum[index])) + parseInt(array[index]);
            });
		}
        console.log(sum);
		document.getElementById(id).innerHTML = sum.join(",");
		return "OK";
	}
};
csv.load("math.csv?", "sum");

"use strict";
document.querySelector("button").addEventListener("click",jsandcssreload);
function jsandcssreload(){
    let d = (new Date()).getTime();
    [...document.querySelectorAll("link")].forEach((elm)=>{
        elm.href = elm.href.replace(/(\.css)\??[0-9]{0,}$/,".css?" + d);
    });
    [...document.querySelectorAll("script")].forEach((elm)=>{
        elm.src = elm.src.replace(/(\.js)\??[0-9]{0,}$/,".js?" + d);
    });    
}

        var obj_input = document.createElement("input");
        obj_input.type = "file";
        obj_input.accept = "image/png,image/jpeg";
        var element = document.getElementById("dropArea");
        element.addEventListener("dragover", function(e) {
            e.preventDefault();
            this.classList.add("dragover");
        });
        element.addEventListener("dragleave", function(e) {
            e.preventDefault();
            this.classList.remove("dragover");
        });
        element.addEventListener("drop", function(e) {
            e.preventDefault();
            element.classList.remove("dragover");
            if (/\.((png)|(jpeg)|(jpg))/i.test(e.dataTransfer.files[0].name) === true) {
                var obj = element;
                obj.innerHTML = e.dataTransfer.files[0].name;
                var imgfiles = e.dataTransfer.files;
                obj_input.files = imgfiles;
                var fr = new FileReader();
                fr.readAsDataURL(obj_input.files[0]);
                fr.onload = function() {
                    obj.style.backgroundImage = "url(" + fr.result + ")";
                    obj.style.backgroundSize = "cover";
                };
            }
        });

document.getElementById("btn1").addEventListener("click", () => {
    const mode = {
        mode0: !document.getElementById("mode0").value ? 8 : document.getElementById("mode0").value,
        mode1: document.getElementById("mode1").checked ? true : false,
        mode2: document.getElementById("mode2").checked ? true : false,
        mode3: document.getElementById("mode3").checked ? true : false,
        mode4: document.getElementById("mode4").checked ? true : false
    };
    const data = {
        txt_cnt: mode.mode0,
        txt1: mode.mode1 ? "0123456789" : "",
        txt2: mode.mode2 ? "ABCDEFGHIJKLMNOPQRSTUVWXYZ" : "",
        txt3: mode.mode3 ? "abcdefghijklmnopqrstuvwxyz" : "",
        txt4: mode.mode4 ? "#$&*@+-" : "",
    };


    // console.log(mode,data);

    let str = "";

    if (mode.mode1 || mode.mode2 || mode.mode3 || mode.mode4) {
        let txt_str = data.txt1 + data.txt2 + data.txt3 + data.txt4;
        do {
            str = "";
            for (let i = 1; i <= data.txt_cnt; i++) {
                str = str + txt_str.substr((getRandomInt(txt_str.length) - 1), 1);
            }
        } while ((() => {
            let flg = [];
            flg[0] = mode.mode1 ? /[0-9]/.test(str) : true;
            flg[1] = mode.mode2 ? /[A-Z]/.test(str) : true;
            flg[2] = mode.mode3 ? /[a-z]/.test(str) : true;
            flg[3] = mode.mode4 ? /[#|$|&|*|@|+|\-]/.test(str) : true;
            
            return (() => {
                let f = true;
                for (const key in flg) {
                    if (!flg[key]) {
                        f = false;
                    }
                }
                return f;
            })();
            return false;
        })() === false);
        document.getElementById("view").value = str;
    } else {
        alert("どれかを選択してください");
    }

});
function getRandomInt(max) {
    return Math.floor(Math.random() * max);
}

onoff = 0;
document.getElementById("c").addEventListener("click",()=>{
    document.getElementById("view").innerHTML = (()=>{
        onoff = !onoff?1:0;
        return onoff?"on":"off";
    })();
});

PM> Install-Package Microsoft.Web.WebView2 -Version 1.0.902.49

        async private void button1_Click(object sender, EventArgs e)
        {

         var result = await webView21.ExecuteScriptAsync(
                "(()=>{let obj = document.querySelectorAll(\"#uamods-topics > div > div > div > ul > li > a\");" +
                "let str = \"\";" +
                "for (let i = 0; i < obj.length; i++)" +
                "{" +
                "str += obj[i].innerText + \"[\" + obj[i].href + \"],\";" +
                "}" +
                "return str;" +
                "})();"
             );
            richTextBox1.Text = result.Replace(",","\n").Replace("\"","");
        }