Flash is pretty lax about requiring semi-colons, so you
can omit them completely as long as your statements are separated by carriage returns (ie on separate lines in the actionscript window) , however I certainly wouldn't advise leaving them out.
With the exception if conditionals (if/else etc) and functions you should put a semicolon at the end of each statement to signify the end of that statement. This also allows you to put several statements/declarations on a single line should you wish to do so:
x=1;y=10;name="bob";age="152";
Obviously this ruins the clarity of your code, so it's not advised.
The closing "}" bracket on an if-statement or function is a way of denoting the end of that function, so the semi-colon isn't really needed there.
However, it is convension that if you write a "function
literal" you put a semi-colon at the end. I have no idea why and it isn't necessary. Below is a fucntion literal and below that is a normal function, just to demonstrate
ActionScript Code:
//function literal (some people put semi-colons after the closing bracket, but not essential)
doSomething = function(){
//code here
};
//standard function (don't put a semi-colon afetr the closing bracket)
function doSomething(){
//code here
}
As faffy says, they are only required to separate statements within a for loop.