5. Implement an array Average function in JavaScript. The function should be defined in the section of a HTML page and called/tested from the document body. The function asks the user for numbers seperated by a single space via a prompt dialog box, stores the numbers in an array returns their average. Note: you need to consider the possibility of the user pressing the OK button without entering any numbers or pressing the Cancel button; you decide how you want to deal with these 2 cases