Multiple if-else statement in javascript for timer

I have a problem with the if-else statement in the code given below. The code below shows a reverse counter from 15 seconds. Now when the counter hits to 10 seconds, it should show a message ("You will be logged out in 10 seconds"). The counter shouldn't stop and when it hits 0 seconds, it should redirect to some other page. The below code works till the time it reaches 10 seconds and shows the message. After that, it just stops. How can I make it work... (add break, continue in the code?)

function setCookie(cname,cvalue,exdays)
{
    var d = new Date();
    d.setTime(d.getTime()+(exdays*24*60*60*1000));
    var expires = "expires="+d.toGMTString();
    document.cookie = cname + "=" + cvalue + "; " + expires;
}
function getCookie(cname)
{
    var name = cname + "=";
    var ca = document.cookie.split(';');
    for(var i=0; i<ca.length; i++) 
    {
        var c = ca[i].trim();
        if (c.indexOf(name)==0) return c.substring(name.length,c.length);
    }
return "";
}

//check existing cookie
cook=getCookie("my_cookie");

if(cook==""){
    //cookie not found, so set seconds=60
    var seconds = 15;
}else{
    seconds = cook;
    console.log(cook);
}

function secondPassed() {
            var minutes = Math.round((seconds - 30)/60);
            var remainingSeconds = seconds % 60;
            if (remainingSeconds < 10) {
                remainingSeconds = "0" + remainingSeconds; 
            }
            //store seconds to cookie
            setCookie("my_cookie",seconds,5); //here 5 is expiry days

            document.getElementById('countdown').innerHTML = minutes + ":" +    remainingSeconds;
            if (seconds == 10) {
                clearInterval(countdownTimer);
                document.getElementById('countdown').innerHTML = "You will be logged out in 10 seconds";

            } else if (seconds == 0) {
                clearInterval(countdownTimer);
                document.getElementById('countdown').innerHTML = "Buzz Buzz";                       
                window.location="http://www.google.com";
            } else {    
                seconds--;
            }
        }
var countdownTimer = setInterval(secondPassed, 1000);

Here is the working code.. http://ift.tt/1yIwlyK