Answers for "how to check if a letter is lowercase or uppercase in javascript"

check if letter is uppercase javascript

const isUpperCase = (string) => /^[A-Z]*$/.test(string)

js test letter lowercase

if (character == character.toLowerCase())
{
  // The character is lowercase
}
else
{
  // The character is uppercase
}
//The problem with this answer is, 
//that some characters like numbers or punctuation 
//also return true when checked for lowercase/uppercase.

// this is the solution for it:
function isLowerCase(str)
{
    return str == str.toLowerCase() && str != str.toUpperCase();
}

check if letter is uppercase javascript

var strings = 'this iS a TeSt 523 Now!';
var i=0;
var character='';
while (i <= strings.length){
    character = strings.charAt(i);
    if (!isNaN(character * 1)){
        alert('character is numeric');
    }else{
        if (character == character.toUpperCase()) {
            alert ('upper case true');
        }
        if (character == character.toLowerCase()){
            alert ('lower case true');
        }
    }
    i++;
}