JSFiddle - React, Tailwind, and code Playground

HTML

<textarea id="myinput"></textarea>
<div id="charcount"></div>

CSS

textarea {
    width:400px;
    height:100px;
}

JavaScript

var charCount = $('#charcount');
$('#myinput').keyup(function () {
    var text = this.value;
    var isChinese = /[\u4E00-\u9FFF\u6300-\u77FF\u7800-\u8CFF\u8D00-\u9FFF]+/.test(text);
    if (!isChinese && (/[^\x00-\x80]+/.test(text))) {
        charCount.text("Error: Neither ASCII nor Chinese Unicode Character Entered");
        return;
    }
    
    var credits = {chinese: [
      [1,60],
      [60,130],
      [130,190]
    ],english: [
        [1,152],
        [152,298],
        [298,450],
        [450,596],
        [602,754]
    ]};
    
    var _credits = credits[isChinese?"chinese":"english"];
    var i;
    for (i = _credits.length; i > 1; i--) {
     if  (text.length >= _credits[i-1][0] && text.length < _credits[i-1][1]) break; 
    }
        
    charCount.text('We will deduct '+ i +' credit for this message per contact. Characters: '+text.length);
});