Nope. 1 is not a property name that can be used with the dotted notation because it begins with a figure. foo.bar().1 + baz() gives: Uncaught SyntaxError:

Nope. 1 is not a property name that can be used with the dotted notation because it begins with a figure. foo.bar().1 + baz() gives: Uncaught SyntaxError: unexpected token: numeric literal The following: foo.bar() .1 + baz() is equivalent to: foo.bar(); .1 + baz(); The parser will find this syntax error, backtrack and insert a semicolon (Automatic Semicolon Insertion applies). Interestingly, I tried to run the following in the browser console: {}.1 And it runs. It gives 0.1. This is probably because {} is interpreted as an empty block (of statements), I guess. The following gives the same result: {};.1 The following is a parse error: ({}).1 I tried the following to convince myself that {} is evaluated as an empty block, so I went further. The following works: {a:2}.1 ... because a: is a label. you really need to try with "two properties" to see a syntax error: {a:2, b:2}.1 Gives: Uncaught SyntaxError: unexpected token: ':' (character 7). A label cannot be introduced after the comma operator... (yes, because it is a comma operator! {a:2, console.log("hello")}.1 prints "hello" and its result is 0.1) (WAT?) edit: {;}.1 and {;;}.1 also work of course.