var interv = 120000; // ms
window._intervalId = undefined;
function startAutoRefresh(){
    window._intervalId = setInterval(function(){
        if (!document.getElementsByClassName('scan active')[0]) {
            document.getElementsByClassName('scan')[0].click();
            console.log('auto scan start');
        }
        else{
            console.log('auto scan skipped, already running');
        }
    }, interv)
}

function stopAutoRefresh(){
    if (window._intervalId){
        clearInterval(window._intervalId);
        window._intervalId = undefined;
    }
    else{
        console.error('stop called without start');
    }
}

startAutoRefresh();