JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>

<script>
var strings = 'abCD12$#!';
var i=0;
var character='';
while (i < strings.length){
    character = strings.charAt(i);
    if (!isNaN(character * 1)){
        alert('character is numric');
        alert(strings.charAt(i));
    }else{
        if (character == character.toUpperCase()) {
            alert ('upper case true');
            alert(strings.charAt(i));
        }
        if (character == character.toLowerCase()){
            alert ('lower case true');
            alert(strings.charAt(i));
        }
    }
    i++;
}
</script>