function changeclassone() {
var NAME = document.getElementById("one");
NAME.className="on";
var NAME = document.getElementById("two");
NAME.className="off";
var NAME = document.getElementById("three");
NAME.className="off";
var NAME = document.getElementById("four");
NAME.className="off";
var NAME = document.getElementById("flash");
NAME.className="one";
}

function changeclasstwo() {
var NAME = document.getElementById("one");
NAME.className="off";
var NAME = document.getElementById("two");
NAME.className="on";
var NAME = document.getElementById("three");
NAME.className="off";
var NAME = document.getElementById("four");
NAME.className="off";
var NAME = document.getElementById("flash");
NAME.className="two";
}

function changeclassthree() {
var NAME = document.getElementById("one");
NAME.className="off";
var NAME = document.getElementById("two");
NAME.className="off";
var NAME = document.getElementById("three");
NAME.className="on";
var NAME = document.getElementById("four");
NAME.className="off";
var NAME = document.getElementById("flash");
NAME.className="three";
}

function changeclassfour() {
var NAME = document.getElementById("one");
NAME.className="off";
var NAME = document.getElementById("two");
NAME.className="off";
var NAME = document.getElementById("three");
NAME.className="off";
var NAME = document.getElementById("four");
NAME.className="on";
var NAME = document.getElementById("flash");
NAME.className="four";
}