HTML
HTML object can embed multiple types of items downloaded from given URL:
- Image - but there's a specialized
<img>tag for that. - Video - similarly, there's a specialized
<video>tag for that. - PDF file
- Text from an external URL.
<object type="text/plain" data={url} />, where the MIME type can be, among others,text/plain,text/csvorapplication/json.
It can be useful in several cases:
PDF preview
Modern browsers can display PDF files. But these files don't have to be displayed in a separate tab or window. When it's necessary to display a PDF file as a part of an existing page, <object> tag can be handy. It won't work in browsers that don't support PDF file format, and in this case it may turn out to be necessary to use a PDF renderer implemented in JavaScript, such as PDF.js.
Text preview
Similarly to PDF preview, the <object> tag may come handy for a quick preview of a raw text file, CSV, JSON etc. from a given URL - without downloading the file with JavaScript. It displays the text without any preprocessing, so it's not a good solution if you need syntax highlighting, formatting, or you need to extract information from the file.
Example
I used <object> tag next to a file upload button, for preview of uploaded file. This way the preview can somehow work for lots file types - including PDF or various text formats - without having to write complicated preview components (and importing large libraries) for each possible type.