What does ‘::’ (double colon) do in JavaScript?

Question

The documentation of some JavaScript APIs shows the following snippets as an example of how to invoke some function:

Answer 1

:: has nothing to do with the number of parameters. You can do that already in JavaScript with a normal comma:

function SomeFunction(param1, param2) {
   //...
}

SomeFunction('oneParam'); // Perfectly legal

Also, based on Tzury Bar Yochay's answer, are you sure you're not looking at something like the following?

$('this::is all one::parameter'); // jQuery selector

Answer 2

Nothing. It is a syntax error.

>>> alert(42342::37438)
SyntaxError: missing ) after argument list

Answer 3

It must be a typo for

<button type="button" onClick="foo.DoIt('72930')">Click</button>

<button type="button" onClick="foo.DoIt('42342::37438')">Click</button>

Answer 4

It was certainly not the case at the time of your question, but right now :: is a valid ES7 operator. It's actually a shortcut for bind.

::foo.bar

is equivalent to

foo.bar.bind(foo)

See an explanation here for examples:

Answer 5

It could be using ECMAScript for XML (ECMA-357 standard) which would imply the double quotes are a XPath operator.

See ECMAScript for XML

Answer 6

In which example did you see that? So far, JavaScript does not have a double colon operator!

The double colon replaced the single-colon selectors for pseudo-elements in CSS3 to make an explicit distinction between pseudo-classes and pseudo-elements. But that is CSS3, not JavaScript! Not At ALL!