这是一个来自Google Maps API开发人员指南的代码示例。我对JavaScript没有超级经验,但我从未见过这种语法。迷惑我的部分是第一部分,他们说“var citymap = {};”然后看似继续声明一堆城市地图键。然后,他们会说“for(var city in citymap){”等。这是一个可行的JavaScript地图制作方法吗?
这是唯一的/在JavaScript中制作地图的正确方法吗?
// Create an object containing LatLng, population.
var citymap = {};
citymap['chicago'] = {
center: new google.maps.LatLng(41.878113, -87.629798),
population: 2842518
};
citymap['newyork'] = {
center: new google.maps.LatLng(40.714352, -74.005973),
population: 8143197
};
citymap['losangeles'] = {
center: new google.maps.LatLng(34.052234, -118.243684),
population: 3844829
}
var cityCircle;
function initialize() {
var mapOptions = {
zoom: 4,
center: new google.maps.LatLng(37.09024, -95.712891),
mapTypeId: google.maps.MapTypeId.TERRAIN
};
var map = new google.maps.Map(document.getElementById("map_canvas"),
mapOptions);
for (var city in citymap) {
// Construct the circle for each value in citymap. We scale population by 20.
var populationOptions = {
strokeColor: "#FF0000",
strokeOpacity: 0.8,
strokeWeight: 2,
fillColor: "#FF0000",
fillOpacity: 0.35,
map: map,
center: citymap[city].center,
radius: citymap[city].population/20
};
cityCircle = new google.maps.Circle(populationOptions);
}
}
很好地解释了。这是我怀疑的。谢谢。 – Aerovistae 2012-03-25 20:01:12