Question

I have just noticed that I can do the following in javascript…

a:b:c:d = "happy days";
a:b:c = function(text){alert(text);};

I cannot however do…

var a:b:c:d = "happy days"; 
// or
var myObj = {prop:a:b:c:d};

I was not expecting this syntax to work under any circumstances. Does anyone have any idea what is going on when I successfully use the ‘a:b=x’ notation?

Answer 1

Quoting the ECMAScript standard: “A Statement may be prefixed by a label. Labelled statements are only used in conjunction with labelled break and continue statements.” A label consists of an identifier and a colon. So a:b:c:d = "happy days"; is just an assignment statement d = "happy days"; prefixed by three labels, which have no effect as such.