JSFiddle - React, Tailwind, and code Playground

by kyleshen

HTML

<textarea id="memo" cols="50" rows="5" maxlength="10"></textarea>

<div id="log"></div>

JavaScript

calculating = function(){
    var maxlength = parseInt($('#memo').attr('maxlength'));
    var NowEntry =  parseInt($('#memo').val().length);
    var left = maxlength - NowEntry;
    console.log(maxlength);
    console.log(NowEntry);
    NowEntry = maxlength <= NowEntry  ? NowEntry : NowEntry+1;
    left = maxlength <= NowEntry ? left : left-1;
    $('#log').html('<div>您已輸入'+NowEntry+'字元，剩餘'+left+'字元</div>');
};

$('#memo').keydown(function(){
   calculating();
});

$('#memo').blur(function() {
    calculating();
});