What's substantive difference between function and Object in javascript? -

when learn js @ first voice object, think maybe function object , object object too.

but when learn prototype, thing different thought.

function helloworld(){                                                                            this.hi = 'world'; } var foo = {      'sth':'happend' };   function bar(){};  bar.prototype = foo; console.log(new bar().sth);  bar.prototype = helloworld; console.log(new bar().hi); 

and print

happend undefined 

then replace bar.prototype = helloworld; bar.prototype = new helloworld(); correct result.

happend world 

i'm newbie, maybe it's stupid question, want know what's wrong in mind? function not object? me? lot..

yes, function object, , can have properties well:

var foo = {}; var bar = function(x){return x+1}; foo.prop = "hello "; bar.prop = "world!"; // works same! alert(foo.prop + bar.prop); 

what's substantive difference between function , object?

well, function object can called - "normal" objects can't:

bar(4); // 5 foo(4); // error: 'foo' not function 

i replace bar.prototype = helloworld; bar.prototype = new helloworld(); correct result

i want know what's wrong in mind?

you must not confuse constructor functions instances created calling them. helloworld object (just bar in example above), it's different object new helloworld() (which inherits helloworld.prototype, , initialised constructor hi property).