Auto-execute javascript functions AND call them later?

Question

I read on many places that you can auto launch js functions on load by doing :

$(function() {     // code... }); 

Or

var myFunc = function() {    // code... }(); 

My question is, how do you call these functions later ? Because the simple declaration

function myFunc() {     // code... } 

can be easily recalled but doesn't auto-launch. I have to manually call them all on load, and that's annoying, take up spaces in the code and it can be an error source if i forgot one.

If you don't understand my explanations, here's an example :

I have a "weight" and a "height" field in my form, and i need to calculate the BMI (Body Mass Index). When the page loads, the weight and height are filled by the database, then i launch the calculation when everything's ready. But later, if the user changes the weight or the height, the BMI have to recalculate immediately. What's the best way to do that ? Using jquery or pure JS, I don't mind.

Thanks.

Answer 1

A reusable immediate function

var reference = (function thename(){      //function body      return thename; //return the function itself to reference  }()); //auto-run   reference(); //call it again reference(); //and again 

Note that calling the function returns a reference to the function you just called.

var anotherReference = reference(); //anotherReference === reference