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>

package com.example

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.text.Editable
import android.widget.EditText
import  android.text.TextWatcher
import android.util.Log
import android.widget.TextView

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        var editText = findViewById<EditText>(R.id.editTextTextN1)
        var textview = findViewById<TextView>(R.id.textView)
        editText.addTextChangedListener(object : TextWatcher {
            override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, after: Int) {

            }

            override fun afterTextChanged(s: Editable?) {

            }

            override fun onTextChanged(s: CharSequence?, start: Int, before: Int, count: Int) {
                Log.d("テキストが入力されました","$s")
                textview.text = s.toString()
            }
        }
        )
    }
}

document.getElementById("Q9_select").innerHTML = (function () {
    let str = "";
    for (var i = 0; i <= 9; i++) {
        str += !i ? "<option value=''> " + "選択してください" + "</option>\n" : "<option value=" + i + ">" + i + "の段</option>\n";
    }
    return str;
})();
document.getElementById("Q9_select").addEventListener("change", function (e) {
    let Q = this.value ? this.value : 0;
    let str = "";
    let view_flg = 1;
    for (var i = 1; i <= 9; i++) {
        let ans = Q * i;
        str += "<p class='h2'><span class='text-primary'>" + Q + "</span> × " + i + "= <span class='Q9_ans' style='visibility:visible'>" + ans + "</span></p>";
    }
    str += "<p class='text-center'><button class='h2 btn btn-primary' id='view'>九九の解を<span id='txt'>非表示に</span>する</button></p>";
    document.getElementById("Q9_view").innerHTML = str;
    document.getElementById("view").addEventListener("click", function () {
        let object = document.getElementsByClassName("Q9_ans");
        for (const key in object) {
            if (Object.hasOwnProperty.call(object, key)) {
                const element = object[key];
                element.style.visibility = view_flg ? "hidden" : "visible";
            }
        }
        view_flg = view_flg ? 0 : 1;
        document.getElementById("txt").innerText = view_flg ? "非表示に" : "表示";
    });
});