Today saw the nesting and recursive function calls, this method is often used.
Learning the definition of static variables declared with the static keyword before the variable, the variable in the function so that it will not release function is completed.
Also learned variable function, that is, after the function variable name in parentheses, in this program is to minimize the use of.
Read the callback function, do not understand what this role, that is a built-in function, call the function, and then passed back to the function parameters.
There are anonymous function, that is not the name of the function can be directly assigned to a variable, then the variable name with parentheses way to achieve function.
