I get the 4 inputs of my form :

let fielsForUppercase = document.querySelectorAll(".uppperFirstLetter");

My function works correctly when I test :

fielsForUppercase[0].value = 'test 1';
fielsForUppercase[1].value = 'test 2';
fielsForUppercase[2].value = 'test 3';
fielsForUppercase[3].value = 'test 4';
function CapitalizeFirstLetter() {
    for (let y = 0; y < fielsForUppercase.length; y++) {
        console.log(fielsForUppercase[y].value.charAt(0).toUpperCase() + fielsForUppercase[y].value.slice(1));
    }
}
CapitalizeFirstLetter();

But I would like to run this function when the user types in the input, I tried this, but it doesn't work :

for (let i = 0; i < fielsForUppercase.length; i++) {
    fielsForUppercase[i].addEventListener("change", CapitalizeFirstLetter);
}