サンプルコード [実行]
<!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">
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8"/>
<title>Sample</title>
<script src="http://maps.google.com/maps?file=api&v=2&key=ABQIAAAAasAJryKxWJnBFVJa487d9hTHGAxTVT7IRADYa-JdYz7xQ8IQZBSthgDZdggYpQHsmm6WYtHstQFfLA" type="text/javascript"></script>
<script type="text/javascript">
//<![CDATA[
var map, httpObj;
window.onload = function() {
map = new GMap2(document.getElementById("gmap"));
map.setCenter(new GLatLng(37, 138), 6);
map.addControl(new GLargeMapControl());
var msec = (new Date()).getTime();
httpObj = GXmlHttp.create();
httpObj.open("get", "./point.csv?cache="+msec);
httpObj.onreadystatechange = function() {
if ((httpObj.readyState == 4) && (httpObj.status == 200)) addMarker();
}
httpObj.send(null);
GEvent.addListener(map, "zoom", addMarker );
GEvent.addListener(map, "moveend", addMarker );
}
function addMarker() {
map.clearOverlays(); // 全てのマーカーを消去（線も消えるので注意）
var count = 0; // 表示するマーカーの数をカウントする変数
var CR = String.fromCharCode(13);
var txt = httpObj.responseText;
var pointData = txt.split(CR);
var area = map.getBounds();
for (var i=0; i<pointData.length; i++) {
var pnt = pointData[i].split(",");
var mx = pnt[0];
var my = pnt[1];
var gpObj = new GLatLng(my, mx);
if (area.contains(gpObj)) {
map.addOverlay(new GMarker(gpObj));
count++;
}
}
document.getElementById("result").innerHTML = "表示したマーカー数："+count;
}
//]]>
</script>
</head>
<body>
<div id="gmap" style="width: 500px; height: 400px"></div>
<div id="result"></div>
</body>
</html>