实测:xml与json速度约差4倍
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：
代码
<!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 msid="13615532361" lng="104.0447" lat="30.684" status="0" info="川A7G222. <br> 力帆体育场店<br> 2010-10-27 12:54:39 " />');
}
var doc = "<current>" + ary.join("") + "</current>";
var t0 = new Date();
var xmlDoc = GXml.parse(doc);
if( ! xmlDoc || ! xmlDoc.documentElement) return;
var markers = xmlDoc.documentElement.getElementsByTagName("marker");
for (var i = 0; i < markers.length; i++) {
var lat = parseFloat(markers[i].getAttribute("lat"));
var lng = parseFloat(markers[i].getAttribute("lng"));
var msid = markers[i].getAttribute("msid");
var status = markers[i].getAttribute("status");
var info = markers[i].getAttribute("info");
}
var t1 = new Date();
alert(t1-t0); //0.57秒
//-----------------------------------
var ary =[];
for(var i=0; i<10000; i++ ){
ary.push('["13615532361",104.0447,30.684,0,"川A7G222. <br> 力帆体育场店<br> 2010-10-27 12:54:39"]');
}
var doc = "[" + ary.join(",") + "]";
var t0 = new Date();
var markers = eval(doc);
for (var i = 0; i < markers.length; i++) {
var lat = parseFloat(markers[i][1]);
var lng = parseFloat(markers[i][2]);
var msid = markers[i][0];
var status = markers[i][3];
var info = markers[i][4];
}
var t1 = new Date();
alert(t1-t0); //0.15秒
//-----------------------------------
var ary =[];
for(var i=0; i<10000; i++ ){
ary.push('{msid:"13615532361",lng:104.0447,lat:30.684,status:0,info:"川A7G222. <br> 力帆体育场店<br> 2010-10-27 12:54:39"}');
}
var doc = "[" + ary.join(",") + "]";
var t0 = new Date();
var markers = eval(doc);
for (var i = 0; i < markers.length; i++) {
// obtain the attribues of each marker
var lat = parseFloat(markers[i].lat);
var lng = parseFloat(markers[i].lng);
var msid = markers[i].msid;
var status = markers[i].status;
var info = markers[i].info;
}
var t1 = new Date();
alert(t1-t0); //0.15秒
}
</script>
</head>
<body onload="initialize()" onunload="GUnload()">
<div id="map_canvas" style="width: 800px; height: 600px"></div>
</body>
</html>
"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 msid="13615532361" lng="104.0447" lat="30.684" status="0" info="川A7G222. <br> 力帆体育场店<br> 2010-10-27 12:54:39 " />');
}
var doc = "<current>" + ary.join("") + "</current>";
var t0 = new Date();
var xmlDoc = GXml.parse(doc);
if( ! xmlDoc || ! xmlDoc.documentElement) return;
var markers = xmlDoc.documentElement.getElementsByTagName("marker");
for (var i = 0; i < markers.length; i++) {
var lat = parseFloat(markers[i].getAttribute("lat"));
var lng = parseFloat(markers[i].getAttribute("lng"));
var msid = markers[i].getAttribute("msid");
var status = markers[i].getAttribute("status");
var info = markers[i].getAttribute("info");
}
var t1 = new Date();
alert(t1-t0); //0.57秒
//-----------------------------------
var ary =[];
for(var i=0; i<10000; i++ ){
ary.push('["13615532361",104.0447,30.684,0,"川A7G222. <br> 力帆体育场店<br> 2010-10-27 12:54:39"]');
}
var doc = "[" + ary.join(",") + "]";
var t0 = new Date();
var markers = eval(doc);
for (var i = 0; i < markers.length; i++) {
var lat = parseFloat(markers[i][1]);
var lng = parseFloat(markers[i][2]);
var msid = markers[i][0];
var status = markers[i][3];
var info = markers[i][4];
}
var t1 = new Date();
alert(t1-t0); //0.15秒
//-----------------------------------
var ary =[];
for(var i=0; i<10000; i++ ){
ary.push('{msid:"13615532361",lng:104.0447,lat:30.684,status:0,info:"川A7G222. <br> 力帆体育场店<br> 2010-10-27 12:54:39"}');
}
var doc = "[" + ary.join(",") + "]";
var t0 = new Date();
var markers = eval(doc);
for (var i = 0; i < markers.length; i++) {
// obtain the attribues of each marker
var lat = parseFloat(markers[i].lat);
var lng = parseFloat(markers[i].lng);
var msid = markers[i].msid;
var status = markers[i].status;
var info = markers[i].info;
}
var t1 = new Date();
alert(t1-t0); //0.15秒
}
</script>
</head>
<body onload="initialize()" onunload="GUnload()">
<div id="map_canvas" style="width: 800px; height: 600px"></div>
</body>
</html>
