First press "Render" and then press "Evaluate".

map = new GMap(document.getElementById("maparea"));
lng = -117.379;
lat = 33.971;
zoom = 6;
map.centerAndZoom(new GPoint(lng, lat), zoom);
map.addControl(new GSmallMapControl());

function button1(event) {
 lng = +(document.getElementById("lng").value);
 lat = +(document.getElementById("lat").value);
 zoom = +(document.getElementById("zoom").value);
 map.centerAndZoom(new GPoint(lng, lat), zoom);
}

function button2(event) {
 marker = new GMarker(new GPoint(lng, lat));
 map.addOverlay(marker);
 marker.openInfoWindowHtml("<a href='http://www.socalcontest.org'>SoCal Regional Contest</a>!");
}

var animationTimer3 = null;
var animationTimer5 = null;

var deltalat;
var deltalng;

function button3(event) {
 if (animationTimer3) return;
 deltalat = +(document.getElementById("deltalat").value);
 deltalng = +(document.getElementById("deltalng").value);
 animationTimer3 = setInterval(animiationLoop3, 500);
}

function animiationLoop3() {
  var center = map.getCenterLatLng();
  map.recenterOrPanToLatLng(new GPoint(center.x + deltalat, center.y + deltalng));
}

var bookmark = 1;

function button4(event) {
 var center = map.getCenterLatLng();
 var z = map.getZoomLevel();
 map.addOverlay(new GMarker(center)); 
 var code = "map.centerAndZoom(new GPoint(" + center.x + "," +
 center.y + "), " + z + ");";
 var html = "<a href='javascript:" + code + "'>" + bookmark + "</a>, ";
 document.getElementById("bookmarks").innerHTML += html;
 bookmark++; 
}

var delta;
function button5(event) {
 if (animationTimer5) return;
 step = 1;
 delta = +(document.getElementById("deltalng").value);
 animationTimer5 = setInterval(animiationLoop5, 50);  
}

function animiationLoop5() {
  if (step % 2 == 0)
    lng += delta;
  else
    lng -= delta;

if (step % 5 == 0) lat -= 0.00005;
  
  map.recenterOrPanToLatLng(new GPoint(lng, lat));
  step++;
}

function button6(event) {
 GEvent.addListener(map, "moveend", function() {
  var center = map.getCenterLatLng();
  var latLngStr = '(' + center.y + ', ' + center.x + ')';
  document.getElementById("message").innerHTML = latLngStr;
 });
}

function stopAnimation(event) {
  if (animationTimer3) clearTimeout(animationTimer3);
  if (animationTimer5) clearTimeout(animationTimer5);
  document.getElementById("deltalat").value = 0.0005;
  document.getElementById("deltalng").value = 0.0005;
  animationTimer3 = null;
  animationTimer5 = null;
}

document.getElementById("button1").onclick = button1;
document.getElementById("button2").onclick = button2;
document.getElementById("button3").onclick = button3;
document.getElementById("button4").onclick = button4;
document.getElementById("button5").onclick = button5;
document.getElementById("button6").onclick = button6;
document.getElementById("stop").onclick = stopAnimation;

Lat: Lng: Zoom:
DeltaLat: DeltaLng:
data.xml www.google.com/apis/maps