xml与json在javascript中解析并使用，速度大约相差4倍。（在IE中测试的结果）。
其中主要不在于eval,与xml parse的时间差别，主要在于属性访问上的差别：
xml中使用这样的方式 markers[i].getAttribute("info")
与json中使用这样的方式 var info = markers[i].info;
相比， xml要慢不少。
以下为测试的详情：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:v="urn:schemas-microsoft-com:vml">
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8"/>
<title>Google Maps JavaScript API Example: Simple Map</title>
<script src="http://maps.google.com/maps?file=api&v=2&key=ABQIAAAAzr2EBOXUKnm_jVnk0OJI7xSosDVG8KKPE1-m51RBrvYughuyMxQ-i1QfUnH94QxWIa6N4U6MouMmBA"
type="text/javascript"></script>
<script type="text/javascript">
//全局变量
var map = null;
function initialize() {
if (!GBrowserIsCompatible()) return;
map = new GMap2(document.getElementById("map_canvas"));
map.addMapType( G_PHYSICAL_MAP );
map.addMapType(G_SATELLITE_3D_MAP);
map.setCenter(new GLatLng(39.9, 116.00), 6);
map.addControl( new GMapTypeControl() );
map.addControl( new GLargeMapControl() );
map.enableContinuousZoom();
GEvent.addListener(map, "mousemove", function(p){
if(!p)return;
window.status = "经纬度 " + (Math.round(p.lng()*100000)/ 100000)+ ", "
+ (Math.round(p.lat()*100000)/ 100000);
});
var t0 = new Date();
for(var i=0; i<100; i++ ){
var home_point = new GLatLng(37.056136+i/1e4,114.457626+i/1e4);
map.addOverlay(new GMarker(home_point));
}
var t1 = new Date();
alert(t1-t0); //1000用时6.3秒
testSpeed();
}
function testSpeed()
{
//-----------------------------------
var ary =[];
for(var i=0; i<10000; i++ ){
ary.push('<marker ms>>
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:v="urn:schemas-microsoft-com:vml">
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8"/>
<title>Google Maps JavaScript API Example: Simple Map</title>
<script src="http://maps.google.com/maps?file=api&v=2&key=ABQIAAAAzr2EBOXUKnm_jVnk0OJI7xSosDVG8KKPE1-m51RBrvYughuyMxQ-i1QfUnH94QxWIa6N4U6MouMmBA"
type="text/javascript"></script>
<script type="text/javascript">
//全局变量
var map = null;
function initialize() {
if (!GBrowserIsCompatible()) return;
map = new GMap2(document.getElementById("map_canvas"));
map.addMapType( G_PHYSICAL_MAP );
map.addMapType(G_SATELLITE_3D_MAP);
map.setCenter(new GLatLng(39.9, 116.00), 6);
map.addControl( new GMapTypeControl() );
map.addControl( new GLargeMapControl() );
map.enableContinuousZoom();
GEvent.addListener(map, "mousemove", function(p){
if(!p)return;
window.status = "经纬度 " + (Math.round(p.lng()*100000)/ 100000)+ ", "
+ (Math.round(p.lat()*100000)/ 100000);
});
var t0 = new Date();
for(var i=0; i<100; i++ ){
var home_point = new GLatLng(37.056136+i/1e4,114.457626+i/1e4);
map.addOverlay(new GMarker(home_point));
}
var t1 = new Date();
alert(t1-t0); //1000用时6.3秒
testSpeed();
}
function testSpeed()
{
//-----------------------------------
var ary =[];
for(var i=0; i<10000; i++ ){
ary.push('<marker ms>>