Javascript - can it only return false?

If I delete -

else
{
    alert('Keyword has accepted');
    return true; 
}

, whole code wont work.

function required(look_for) 
{
    var empt = look_for;
  
    if (empt.value.length == 0)
    {
        alert("Please input a Keyword"); 
        return false;
    }
    else
    {
        alert('Keyword has accepted');
        return true; 
    }
}