Window.close()

The Window.close() method closes the current window, or the window on which it was called.

This method can only be called on windows that were opened by a script using the Window.open() method. If the window was not opened by a script, an error similar to this one appears in the console: Scripts may not close windows that were not opened by script.

Note also that close() has no effect when called on Window objects returned by HTMLIFrameElement.contentWindow.

close()

//Global var to store a reference to the opened window
let openedWindow;

function openWindow() {
  openedWindow = window.open('moreinfo.htm');
}

function closeOpenedWindow() {
  openedWindow.close();
}