NavigationHelpButton

Name	Type	Description
options	object	对象，具有以下属性: Name Type Default Description container Element | string 将包含小部件的DOM元素或ID。 instructionsInitiallyVisible boolean false optional 如果导航指令最初应该是可见的，则为True;否则, false.

Throws:

• DeveloperError : id为"container"的元素在文档中不存在。

Example:

// In HTML head, include a link to the NavigationHelpButton.css stylesheet,
// and in the body, include: <div id="navigationHelpButtonContainer"></div>

const navigationHelpButton = new Cesium.NavigationHelpButton({
    container : 'navigationHelpButtonContainer'
});