Turn from: http://segmentfault.com/q/1010000000135703
Common format: (function () {/* code */}) (); Explanation: The first pair of parentheses of the enclosing function (function () {}) return an unnamed function to the script, followed by an empty bracket that immediately executes the returned unnamed function, with the parameters of the anonymous function in parentheses. Function: You can use it to create namespaces, as long as you write all of your code in this particular function package, then the outside can not access, unless you allow (variable before the window, so that the function or variable becomes global). The code for each JavaScript library is basically this form of organization.
To sum up, the function is performed primarily anonymously and automatically, and the code is already running when interpreted. Other wording
(function () {/* * Code/} ());
! function () {/* code */} ();
~function () {/* * Code/} ();
-function () {/* * Code/} ();
+function () {/* * Code/} ();
Recommended reading: Call-now function expression
