const tekst = document.getElementById("stiligtekst");
const tekstStr = tekst.textContent;
const splitta = tekstStr.split("");
tekst.textContent ="";
for (let i =0; i < splitta.length; i++) {
    tekst.innerHTML +="<span>" + splitta[i] + "</span>";
}

let char = 0;
let timer = setInterval(onTick, 100);

function onTick(){
    const span = tekst.querySelectorAll('span')[char];
    span.classList.add('stilig');
    char++;
    if(char === splitta.length) {
        complete();
        return;
    }

    function complete(){
        clearInterval(timer);
        timer = null;
    }
}