页面点击按钮下载excel（原生js)

　　　　　　　　　 let els = document.getElementsByTagName(‘iframe‘);
                if(els.length > 0){
                    for(let i = 0;i < els.length; i++){
                        document.body.removeChild(els[i]);
                    }
                }
                let el = document.createElement(‘iframe‘);
                el.src = `${url}/region/exportCommodityData?regionId=${this.regionId}`;
                el.style.display = ‘none‘;
                document.body.appendChild(el);