If you find yourself inquiring about this, chances are you're not very familiar with PHP or other Server Side scripting languages. If avoiding Javascript is also a concern for you, then the simplest and most effective solution would be to use IFRAMEs.
1) Begin by placing the content that needs to be repeated into a separate file called content_to_be_repeated.html
.
2) Then insert the following code wherever you want the content to appear on each page:
<iframe src="http://www.content_to_be_repeated.html" width="..." height="..."></iframe>
Adjust the width and height attributes in pixels (or as needed) based on your requirements.
If you wish to remove the default scrollbars from the iframe, you can do so using the following code:
<iframe src="http://www.content_to_be_repeated.html" width="..." height="..." scrolling="no"></iframe>
It's worth noting that the scrolling attribute has been deprecated in HTML 5 (although it will still work). For improved practice, consider using this alternative method:
<iframe src="http://www.content_to_be_repeated.html" width="..." height="..." style="overflow: hidden;"></iframe>