Bookmarks for position on page

When reading long texts, it sometimes becomes necessary to return to the beginning of the text. It would be convenient if there was an opportunity to put something like bookmarks, but with a memory position in the browser. As, for example, in vim - on any line pressed mx, where x is any letter. Then, after any movement through the file, you can press' x and again find yourself on the same line.
Perhaps the community knows some scripts or add-ons for Opera / Fox that allow you to do something similar for web pages?