Assigning xmlhttprequest.responseText to a variable

Question

The script below returns a ReferenceError: notifs is not defined.

Ideas greatly appreciated.

var xhttp = new XMLHttpRequest();

xhttp.onreadystatechange = function()
{
    if (this.readyState == 4 && this.status == 200)
    {
        notifs = this.responseText;         
    }
};

xhttp.open("GET", "Space/notifs.php", true);
xhttp.send();
notif = notifs.split(",");