index.js

function validation (){
    if (document.Formfill.Username.value==""){
        document.getElementById("result").innerHTML="Enter Username";
        return false;

    }
    else if (document.Formfill.Username.value.length<6){
            document.getElementById("result").innerHTML="At least six letters required";
            return false;
    
    }
    else if (document.Formfill.Email.value == ""){
        document.getElementById("result").innerHTML="Enter email ID ";
        return false;

            }
    else if (document.Formfill.Password.value == ""){
                document.getElementById("result").innerHTML="Enter Password ";
                return false;
    }
    
    else if (document.Formfill.cPassword.value=="")
        {document.getElementById("result").innerHTML="Enter Confirm Password";
        return false;
        }
        else if (document.Formfill.cPassword.value !== document.Formfill.Password.value){
            document.getElementById("result").innerHTML="Password Doesn't match";
            return false;
    }

    else if (document.Formfill.Password.value<6){
            document.getElementById("result").innerHTML="Password must be at least 6 characters";
            return false;
                }
    else if (document.Formfill.Password.value == document.Formfill.cPassword.value){
                    popup.classList.add("open-slide")
                    return false;
            }

}
var popup = document.getElementById("popup");
function CloseSlide(){
    popup.classList.remove("open-slide");
}