In my last project I needed a function in JavaScript that will execute itself as soon as it’s ready. My first idea was something like that:

// declare function
function myFunction() {
	alert('Hello world!');
}
// run it when DOM is ready with help of jQuery
$(document).ready(function() {
	myFunction();
});

but in the back of my mind I knew there is a better way. A little bit of googling resulted in something unbelievably simple like this:

(function() {
	alert('Hello world!');
})();

If you need you can pass arguments as you’d normally do:

(function( arg ) {
	alert('Hello world! '+arg);
})(9999);

Quick and simple