Please read first about snippets and how it use in FlashDevelop.
Here i want to tell you about aSnippet. aSnippet enables you to keep all of your frequently used code snippets (As3, As2, Js, PHP, HTML, MXML…) in one place that’s accessible from any computer. Also //aSnippet is also available via any browser, no download required.
Download and install aSnippet Flash extension:
Download and install aSnippet AIR Aplication: