官方：http://openlayers.org/en/latest/examples/lazy-source.html
<!DOCTYPE html> <html> <head> <title>Lazy Source</title> <link rel="stylesheet" href="https://openlayers.org/en/v4.2.0/css/ol.css" type="text/css"> <!-- The line below is only needed for old environments like Internet Explorer and Android 4.x --> <script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script> <script src="https://openlayers.org/en/v4.2.0/build/ol.js"></script> <style> button.code { font-family: Monaco,Menlo,Consolas,"Courier New",monospace; font-size: 12px; padding: 5px; margin: 0 5px; } </style> </head> <body> <div id="map" class="map"></div> <button id="set-source" class="code">layer.setSource(source)</button> <button id="unset-source" class="code">layer.setSource(null)</button> <script> var source = new ol.source.OSM(); var layer = new ol.layer.Tile(); var map = new ol.Map({ layers: [layer], target: 'map', view: new ol.View({ center: [0, 0], zoom: 2 }) }); document.getElementById('set-source').onclick = function() { layer.setSource(source); }; document.getElementById('unset-source').onclick = function() { layer.setSource(null); }; </script> </body> </html>