我开始学习OpenStreetMap / OpenLayers API,在我的Web应用程序中放置地图。虽然我已经掌握了地图本身,但我发现包含地图的div不会停留在我放置它的位置。以下是我的代码:
maptest.htm
<html>
<head>
<title>OpenStreetMap Test</title>
<script language="JavaScript" src="/resources/OpenLayers-2.13.1/OpenLayers.js"></script>
<script language="JavaScript" src="/resources/proj4js/lib/proj4js-combined.js"></script>
<script language="JavaScript" src="maptest.js"></script>
</head>
<body onload="init()">
<h2>OpenStreetMap Test</h2>
<div id="map" style="border: 1px solid black; margin-left: auto; margin-right: auto; margin-top: 10%; height: 300px; width:300px;"></div>
</body>
</html>
maptest.js
function init() {
Proj4js.defs["EPSG:27700"] = "+proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 +x_0=400000 +y_0=-100000 +ellps=airy +datum=OSGB36 +units=m +no_defs ";
var EPSG27700 = new OpenLayers.Projection("EPSG:27700");
var EPSG900913 = new OpenLayers.Projection("EPSG:900913");
var map = new OpenLayers.Map("map",{
controls: [
new OpenLayers.Control.Navigation(),
new OpenLayers.Control.PanZoomBar(),
new OpenLayers.Control.LayerSwitcher({'ascending':false}),
new OpenLayers.Control.ScaleLine(),
new OpenLayers.Control.KeyboardDefaults()
]});
var OSM = new OpenLayers.Layer.OSM("OpenStreetMap");
var OSMcycle = new OpenLayers.Layer.OSM("OSM Cycle", ['http://a.tile.thunderforest.com/cycle/${z}/${x}/${y}.png',
'http://b.tile.thunderforest.com/cycle/${z}/${x}/${y}.png',
'http://c.tile.thunderforest.com/cycle/${z}/${x}/${y}.png']);
map.addLayers([OSMcycle,OSM]);
var position = new OpenLayers.LonLat(321550,507250).transform(EPSG27700,EPSG900913);
var markers = new OpenLayers.Layer.Markers("Markers");
map.addLayer(markers);
markers.addMarker(new OpenLayers.Marker(position));
var zoom = 13;
map.setCenter(position,zoom);
}
没有
onload="init()"
,这个 div 在页面水平居中,并且距离顶部有一小段距离。但是,调用 init()
后,该 div 会回到左侧,位于标题下面。它仍然具有正确的大小和边框,因此 CSS 样式并未完全被忽略,但我不明白为什么它无法保持在位置上?我尝试将 CSS 放入样式表中而不是内联,结果仍然相同。
!important
声明覆盖现有的边距,它应该只关心 div 内部的内容,而不影响其位置。 - Iain