I don't know what I'm doing wrong. Can someone explain to me the else statement for this challenge?

With an else statement in any programming language, you are never checking for a conditional. Your first if checks to isAdmin variable, the else if checks the isStudent variable. If both of those are false then you don't know who the person is and you don't pass a third argument.

if ( isAdmin ) {
    alert('Welcome administrator');
} else if (isStudent) {
    alert('Welcome student');
} else {
  alert("Who are you?");
}

This code is what you are looking for. Just to reiterate what I said earlier, you are already checking the only possible options for those 2 variables, therefore no third conditional needs to be checked. If you were checking something else about the variables then you would use an 'else if' statement rather than an 'else' statement.

Else is the catch-all clause, so you don't need to evaluate anything. Think of it as saying, "Okay, none of my tests came back as true, so for every other case - do this."

if ( isAdmin ) {
    alert('Welcome administrator');
} else if (isStudent) {
    alert('Welcome student');
} else (isAdmin === isStudent){
  alert("Who are you?");
}

Hi Sirin Srikier you else statement is wrong.The right code is

var isAdmin = false;
var isStudent = false;

if ( isAdmin ) {
    alert('Welcome administrator')
} else if (isStudent) {
    alert('Welcome student')
} else {
alert("Who are you?");
}