Sometimes, we need real-time detection of URLs to be judged, operation, handling, etc.
We need to watch the monitor, then direct manipulation
We need to '$ route.path' attribute to monitor and requires quotes, then as long as a page change occurs, we will be able to capture real-time routing of the page
But sometimes we also need created () {} life cycle to be processed this. $ Route.path route, to prevent just started to open the page, the problem can not be displayed