I found that every time I go to the next page of a manga chapter there is always this floating 'x' button.
I tried to find out if it only happens once but when I go to the next page it is there again.
If its not there, then when I refresh the page it always pops up.
I tried other sites but it won't appear. Also it only shows on the chapter page.
it shows "javascript:void(0)" so its probably nothing but I just want to make sure if its the site or my computer doing it.
here is a picture of it
2nd panel at the bottom.
upper right part of the panel
Spoiler