a method is named and attached to an object. so, for example, a method is like a function but is contained inside a class. its scope is limited to that class, and cannot affect variables outside that class, even global variables. if you need to affect a variable outside of a class, just use a function (or routine) that is not contained in a class. 

a function is named and returns a value. 

a routine is like a function but does not need to return a value. 

a procedure is named and may or may not return a value, but receives parameters. 

i think the distinctions between a function and a routine are sort of old school. i don‘t think that distinction is important anymore. 

so a function is like 
function addOne(n) { 
　　return n++; 
} 

routine is like 
function doStuff(){ 
　　makeStuffHappen(); 
} 

and a method is like 
thing.destroy(){ 
　　thing.destroyed = true; 
} 

a procedure is like 
makeApples(x){ 
　　makes x apples 
} 


edit: typos and made bad examples>.<;

What is the difference between routine , method , procedure , function ? please explain it with example?