Javascript Variable Scope Caveats

I ran into a strange Javascript variable scope issue. I am not satisfied with the documentation I found so far, hence this post:

• A variable aaa declared outside of a function is global.
• If a function f1 declares a aaa variable in its code using var, all modifications made to this variable is local and the global aaa variable is not impacted.
• If one uses the f1 local aaa variable in f1 code before it is declared, Javascript will consider it undefined.
• If a function f2 does not declare a local aaa variable in its code, it can access the global aaa variable by using its name. All modifications are registered in the global variable.
• Passing a global variable as a parameter to a function, and modifying this parameter inside that function does not modify the global variable.

Accessing Environment And System Variables On Windows 7

This is a reminder describing how to access environment and system (including path) variables under Window 7:

1. Open Windows Explorer.
2. On the left part of the screen, select the Computer icon.
3. Right-click this icon and select properties.
4. A window will open, select Advanced System Settings.
5. A System Properties windows will open.
6. At the bottom, click Environment Variables.