在div中加载内容

var divElement = document.getElementById("yourDivId");

var xhr = new XMLHttpRequest();
xhr.open("GET", "yourContentUrl", true);
xhr.onreadystatechange = function() {
  if (xhr.readyState === 4 && xhr.status === 200) {
    var content = xhr.responseText;
    divElement.innerHTML = content;
  }
};
xhr.send();

divElement.innerHTML = content;

var cos = new COS({
  SecretId: 'yourSecretId',
  SecretKey: 'yourSecretKey'
});

var params = {
  Bucket: 'yourBucketName',
  Region: 'yourBucketRegion',
  Key: 'yourContentKey',
  Expires: 3600 // URL有效期，单位为秒
};

cos.getPresignedUrl('getObject', params, function(err, url) {
  if (!err) {
    divElement.innerHTML = '<iframe src="' + url + '" width="100%" height="100%"></iframe>';
  }
});