indexOf (JavaScript Array Method)

const tnwText = "Hello Dear All, I am Thet Naing Win. Welcome to TNW (Web Service & ICT Solutions)";

function tnwFun1(){
    document.getElementById("demo").innerHTML = tnwText;
}

function tnwFun2(){
    const tnwSearch = document.getElementById("search").value;
    const result = tnwText.indexOf(tnwSearch);
    document.getElementById("demo").innerHTML = "The search text is fount at " + result;
}