//calling the function in window.onload to make sure the HTML is loaded
window.onload = function() {
     var posLeft = 0;
     var posTop = 150;
    //our box element
    var box = document.getElementById('box');
    var t = setInterval(move, 10);
    var moveDown = setInterval(cac, 10);

    function move() {
        if(posLeft >= 150) {
            clearInterval(t);
        }
        else {
            posLeft += 1;
            box.style.left = posLeft+'px';
        }
    }
    function cac() {
        if(posLeft >= 150 && posTop >= 0) {
            posTop -= 1;
            box.style.bottom = posTop+'px';

        }
        else if(posTop == 0) {
            clearInterval(moveDown);
        }
    }
};