获取iframe高度

// iframe已加载完毕
            if (iframe.attachEvent) {
                iframe.attachEvent('onload', function () {
                    let offsetHeight = document.getElementById('iframe').contentWindow.document.documentElement.offsetHeight;
                    that.iframeHeight = offsetHeight;
                })
            } else {
                iframe.onload = function () {
                    // iframe加载完毕以后执行操作
                    let offsetHeight = document.getElementById('iframe').contentWindow.document.documentElement.offsetHeight;
                    that.iframeHeight = offsetHeight;
                }
            }

注意这里会出现跨域问题