setInterval 每秒钟调用

<script>
    $(function () {

        $('.zan').click(function () {


            var font_size = 15;
            var top = 5;
            var left = 5;
            var opay = 1;

            var tag = document.createElement('span');
            tag.style.fontSize = font_size + 'px';
            tag.style.color = "green";
            tag.innerHTML = "+1";
            tag.style.left = left + 'px';
            tag.style.top = top + 'px';
            tag.style.opacity = 1;
            $(this).append(tag);
            

            var obj = setInterval(function () {

                font_size += 1;
                top -= 1;
                left += 3;
                opay -= 0.2;

                if (opay < 0) {
                    clearInterval(obj);
                    $(tag).remove();
                }

            }, 100)

        })
    })
</script>