Referencing a file for a certain area of a webpage?
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Is there any way to make an area of a webpage reference another HTML file? For instance, if I have a sidebar that shows up on every page of my site. Eventually, information on it is going to get changed. Instead of having to go to **every** page to change it, is there a way to make that area of the page another HTML file entirely, and then just reference it, so I only have to edit it once for it to affect the whole site? Thanks!