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我仍然对JavaScript没有经验,并试图理解此代码 -.addOn在本传单示例代码中如何工作/执行?
什么时候/如何执行info.onAdd而不是专门调用w/o参数?
根据传单文档,这是一个本地方法,但函数分配给名称?
var info = L.control();
info.onAdd = function (map) {
this._div = L.DomUtil.create('div', 'info'); // create a div with a class "info"
this.update();
return this._div;
};
// method that we will use to update the control based on feature properties passed
info.update = function (props) {
this._div.innerHTML = '<h4>US Population Density</h4>' + (props ?
'<b>' + props.name + '</b><br />' + props.density + ' people/mi<sup>2</sup>'
: 'Hover over a state');
};
info.addTo(map);