var newWin = window.open(url);             

    if(!newWin || newWin.closed || typeof newWin.closed=='undefined') 
    { 
        //POPUP BLOCKED
        alert('blocked');
    } else {
        alert('enabled');
    }

This code only works for first time when I newly loaded site in chrome. But once I allow popup and agin disabled it from chrome site setting still it opens window and gives alert as 'enabled'