declare a global variable inside a function javascript code example

Example 1: javascript define global variable

window.myGlobalVariable = "I am totally a global Var"; //define a global variable
var myOtherGlobalVariable="I too am global as long as I'm outside a function";

Example 2: create global variable inside function JavaScript

<script>
function foo() {
    window.yourGlobalVariable = ...;
}
</script>