Calling a function that's defined inside a function

*Is there a way to call a function defined inside another function in javaSCRIPT? For example:

window.onload() = function() {
    function my_function(){
        print("Blah");
    };
};

function function_two(){
    my_function();
};

Is there a way to do something like the above (calling my_function in function_two even though it's defined inside the window.onload() function)? In my actual code, which also uses the raphael.js library, I'm trying to write a button in HTML, which using the onClick function, calls a function(like function_two) that runs the function defined in window.onload() (like my_function). However the console says that the my_function is undefined.