Add 1 to variable Starting from random number AS3 - actionscript-3

Question

I am in the process of creating an interactive map which gives users the option of clicking on a random site, viewing the content and then either going back to the overview, or continuing on to the next site.
I am having trouble adding 1 to the site number, when the users click "next site". Instead of continuing on to the next site, it goes on from a random number.
My code for the view site button
vmsite1.addEventListener(MouseEvent.MOUSE_DOWN, mouseDownHandlervmsite1);
function mouseDownHandlervmsite1(event:MouseEvent):void
{
gotoAndStop(33); // WHERE THE DYNAMIC CONTENT LOADS
var siteNumber = 1;
}
My code for the next button:
next_site1.addEventListener(MouseEvent.MOUSE_DOWN, mouseDownHandlernext_site1);
function mouseDownHandlernext_site1(event:MouseEvent):void
{
siteNumber = siteNumber;
if (siteNumber <= 29) {
siteNumber ++;
}
else {
siteNumber = siteNumber;
}
// UNLOAD THE PREVIOUS SLIDE SHOW
myLoader.unload();
SiteNumberText1.text = siteNumber.toString();
site1scroll.scrollTarget = field;
loadData();
// LOAD THE SLIDE SHOW
var urlforswfcomp2:URLRequest = new URLRequest(URLSWF + siteNumber + imgext);
myLoader.load(urlforswfcomp2);
}
I have had a look through the AS3 guide on the Adobe website, but I can't find an issue similar to mine.
http://help.adobe.com/en_US/ActionScript/3.0_ProgrammingAS3/WS5b3ccc516d4fbf351e63e3d118a9b90204-7fcf.html
http://www.adobe.com/devnet/actionscript/learning/as3-fundamentals/operators.html
Thanks in Advance!

Answer 1

I moved my siteNumber variable definition outside the button code, and it worked. This is my new view more button code.
var siteNumber:int = 0;
vmsite1.addEventListener(MouseEvent.MOUSE_DOWN, mouseDownHandlervmsite1);
function mouseDownHandlervmsite1(event:MouseEvent):void
{
gotoAndStop(33);
siteNumber = 1
}