To get the current URL of the page you opened in the browser using JavaScript you can rely on the location property exposed by the browser on the window object:
window.location
Since window is the global object in the browser, the property can be referenced as
location
This is a Location object which has many properties on its own:

The current page URL is exposed in
location.href
Other properties of location provide useful information:
| Code | Description |
|---|---|
location.hostname | the host name |
location.origin | the origin |
location.hash | the hash, the part that follow the hash # symbol |
location.pathname | the path |
location.port | the port |
location.protocol | the protocol |
location.search | the query string |