This character is "OGHAM SPACE MARK"[1], which is a space character. So the code is equivalent to alert(2+ 40). From what I know, any unicode character in the Zs class is a white space character in JS[2], but there don't seem to be that many[3]. However, JS also allows unicode characters in identifiers[4], which lets you use interesting variable names like ಠ_ಠ