实测:xml与json速度约差4倍
2010-11-03 08:22:24 来源:WEB开发网核心提示:xml与json在javascript中解析并使用,速度大约相差4倍,实测:xml与json速度约差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
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 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>
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