Actionscript is made up of Classes
Classes have methods and properties commonly called Functions and Variables
in actionscript 2 some properties start with an underscore. _root _x _y _xmouse and so on
the Movieclip class built into flash has properties and Methods.
so when you use a fullstop it is telling it where to go so lets say you draw a circle and make it a movieclip, it can now use the methods and properties within the Movieclip CLASS.
so it can have a _x and _y property and to access it you use the name of the movieclip and then a . to access the property so..
circle._x
this tell flash your working with the circel movieclip's _x property. because you made it a movieclip flash knows it can use the Movieclip class allowing the _x
there are other classes like sound classes.. these do nont have a _x property and you will get an error doing
mySound:Sound = new Sound;
mySound._x = 10;
flash will look in the sound class and go WOAH!! there is No _x Property what the hell?!?? and go Pfft Nup here have an error!!
different languages use different symbols
Actionscript uses the . so circle.property/method
php uses => circle=> property/method
:)
i don't know i just pulled this from my arse it's probably completely wrong but you don't really need to know why he dot is there just to know you must use it if you want the circle to be at 10 x and 10 y you cant do
circle x = 10
circle y = 10
or
circle.x = 10;
circle.y= 10;
^ that is AS3
as 2 must be
circle._x = 10;
circel._y = 10;
don't forget to end your statements with a ; like i have done a few times.. AS2doesn't require it but it's good pactice.. i beleive AS3 needs it :s