Tutorial Global Variables

Declare variable outside of the function...
var oneVariable;

function setVariable(){
oneVariable = "Variable set from within a function!";
}

function getVariable(){
alert(oneVariable); // Outputs "Variable set from within a function!"
}
Or... attach it to the window object
function setValue() {
window.myValue = "test";
}

function getValue() {
alert(window.myValue);