According to the definition of object backup content that will be displayed when the object is rendered unsuccessfully is the content of the elements. More precisely, it consists of all child elements of an object , except for param elements. In fact, the fragmentary code in the question contains such fallback content: the internal element of the object is the fallback content for the outside. To get a reserve for return, place it inside the internal element of object ; it can be any content, including text:
<p><object classid="..." height="..." width="..."><param name="..."value="..."> <param name="..." value="..." /><param name="..." value="..." /> <object data="..." height="..." type="..."><param name="..." value="..." /> <param name="..." value="..." />This is fallback content.</object></object></p>
Note. If the backup or alternative content means that the text is not displayed when the attachment of the object is successful, that is, a video presentation is displayed.