<iframe id="report_id" src="./query.html" style="width: 100%;height: 450px;"  frameborder="0">
                </iframe>
//初始化方法
init(){
           //发送请求得到html数据
        this.$http.get(this.$route.query.url).then(res =>{
                this.form=res;
                var iframeWin = this.$refs['report_id'].contentWindow;
                   //向子页面发送参数
                iframeWin.postMessage({
                    url: this.$route.query.url,
                    data:res //页面html代码res
                }, '*');
            });
}

<iframe id="app" name="app"  style="width: 100%;height: 650px;"  frameborder="0">
            
  <script type="text/javascript">
    window.URL="";
    window.onload=function(){
            //通过监听事件接收参数
        window.addEventListener("message", function(e){
           var iframe = window.frames['app'];
            //打开iframe.document
            iframe.document.open();
            //iframe.document写入html数据
            iframe.document.write(e.data.data);
            //iframe.document关闭
            iframe.document.close();
        });
    }

</script>

const iframe=window.frames['_print_pdf_frame'];  

$("iframe[name='_print_pdf_frame']").on("load",function(){
                iframe.window.focus();
                iframe.window.print();
});
        
iframe.window.focus();
iframe.location.href=url;//赋值iframe的路径

//导出pdf按钮事件
$(`.export-pdf`).click(function(){
        const urlParameters=buildLocationSearchParameters();
        const url=window._server+'/pdf'+urlParameters;
        windowOpen(url,'.pdf');

    });

function windowOpen(url,typeName){
    var xhr = new XMLHttpRequest();
    var fileName = window.fileName + typeName; // 文件名称
    xhr.open('GET', url, true);
    xhr.responseType = 'blob';
    xhr.setRequestHeader('token',window.token);
    xhr.onload = function(res) {
        if (this.status === 200) {
            var type = xhr.getResponseHeader('Content-Type');
            var blob = new Blob([this.response], {type: type});
            if (typeof window.navigator.msSaveBlob !== 'undefined') {
                /*
                 * For IE
                 * >=IE10
                 */
                window.navigator.msSaveBlob(blob, fileName);
            } else {
                /*
                 * For Non-IE (chrome, firefox)
                 */
                var URL = window.URL || window.webkitURL;
                var objectUrl = URL.createObjectURL(blob);
                if (fileName) {
                    var a = document.createElement('a');
                    if (typeof a.download === 'undefined') {
                        window.location = objectUrl;
                    } else {
                        a.href = objectUrl;
                        a.download = fileName;
                        document.body.appendChild(a);
                        a.click();
                        a.remove();
                    }
                } else {
                    window.location = objectUrl;
                }
            }
        }
    }
    xhr.send();
};

相关资料参考：
XMLHttpRequest 对象
XMLHttpRequest 及其open()的用法_小木木的开发日常-CSDN博客