题解 | #直角三角形#

var triangle = document.querySelector('.triangle');
            // 补全代码
            var fragment = document.createDocumentFragment();
            var star = '';
            for(let i = 0;i<3;i++){
                var span = document.createElement('span');
                star+='*';
                span.innerText = star;
                var br = document.createElement('br');
                fragment.appendChild(span).appendChild(br)
            }
            triangle.appendChild(fragment)