1. Direct binding mode (default binding mode) has the lowest priority
For normal function, this is the window (prerequisite: the function is called when there is no front.)
2. implicit binding way higher priority than directly binding,
As object methods to call a function (premise: when the function is called with the front.)
Implicit binding manner Note: If the continuous method of operation of the object appears, this use of the principle of proximity
3. The explicit binding (apply call bind all three binding mode)
Usage: Add the function name
Rearmost apply call used when the function execution function definition when used in the bind function in
4.new binding way
Priority> new explicit binding mode of binding,> direct binding mode