JS 解决 window.location.href 下载文件时，一次点击产生两次下载+页面跳转问题

请求被覆盖，原来代码

function download(url){
 window.open(url);
}

没有后端配合的情况下改成

function download(url){
  //获得id为downLoadListFrame的frame
  var divFrame = window.parent.document.getElementById("downLoadListFrame")
  //判断是否存在，如果存在先移除，再重新创建
  if (divFrame != null) {
      window.parent.document.body.removeChild(divFrame)
  }
  //重新创建
  var iframe = window.parent.document.createElement("iframe");
  iframe.setAttribute("id", "downLoadListFrame");
  //download_file.id = "downFrame";
  window.parent.document.body.appendChild(iframe);
  divFrame = window.parent.document.getElementById("downLoadListFrame");
  //隐式调用，（注意：window.parent.document 适应对于，farme内部代码，调用frame 外部dom；如果项目未用frame，改写成 document即可）
  divFrame.src = url;
  divFrame.style.display = "none";
}

如果请求后端接口去下载文件流的方式

function download(params, downloadName, url,type){
  let that = this;
  let data = params;
  let xhttp = new XMLHttpRequest();
  xhttp.onreadystatechange = function () {
    let a;
    if (xhttp.readyState === 4 && xhttp.status === 200) {
      // for ie 10+
      if (window.navigator.msSaveBlob) {
        window.navigator.msSaveOrOpenBlob(xhttp.response, downloadName);
        return;
      }
      a = document.createElement('a');
      a.href = window.URL.createObjectURL(xhttp.response);
      a.download = downloadName;
      a.style.display = 'none';
      document.body.appendChild(a);
      a.click();
    }
  };
  let mothed = type?type:'POST';
  xhttp.open(mothed, process.env.VUE_APP_BASE_API + url);
  xhttp.setRequestHeader("Content-Type", "application/json");
  xhttp.setRequestHeader("token", getToken() || ''); //根据实际情况是否要加token
  xhttp.responseType = 'blob';
  xhttp.send(JSON.stringify(data));
}

params入参， downloadName名称，, downloadUrl下载地址，type请求类型get/post