Functions, Functions, Functions!

functions.jsx

function main() {
    alert("This is a declared function and is invoked by calling it by name from suspend history.");
}
app.activeDocument.suspendHistory("Run script", "main()");

// or

(function (){
    alert("This is an anonymous self-invoking function! Also known as an 'Immediately Invoked Function Expression' or (IIFE).");
}());

// or

main("parameter");

function main(parName) {
    alert("This is a declared function and is invoked by calling it by name. It also includes a passed " + parName + "!");
}