i'll try to make form validation by giving the background colour and focus to each input when input is empty but, it turns out even though i fill the input, it still focus on the first input. It is not continue to check on the next input

I have tried with this code

    var fName=document.getElementById("in_fName");
    var lName=document.getElementById("in_lName");

//first name validation
        if (fName.innerHTML===""){
            alert("he");
            fName.style.background="#DE8971";
            fName.style.color="#FFE9D6";
            fName.focus();
        } else {
            alert("here");            
            fName.style.background="white";
            fName.style.color="black";
            return false;
        }

       //last name validation
       if (lName.innerHTML===""){
             lName.style.background="#DE8971";
             lName.style.color="#FFE9D6";
            lName.focus();
        }