let startNum = 0;
let endNum = 15;
const duration =  10; // 1000 milliseconds 

$w.onReady(function () {
    setInterval(()=> {
        countUp();  
    }, duration);
});

function countUp() {
 if (startNum <= endNum ){   
        $w('#text320').text =  startNum.toLocaleString().toString();
        startNum++;
    }
}