<div class="box"></div>
    <script>
        var div = document.querySelector('div');
        var str = "我叫刘少辉，我爱你们" ;
        var index = 0
        function write() {
            if (index < str.length) {
                div.innerHTML += str[index];
                index++;
            }
            
        }
        setInterval(write.bind(),200)
        
    </script>