files/en-us/web/api/screendetailed/top/index.md
{{APIRef("Window Management API")}}{{seecompattable}}{{SecureContext_Header}}
The top read-only property of the
{{domxref("ScreenDetailed")}} interface is a number representing the y-coordinate (top edge) of the total screen area inside the OS virtual screen arrangement, relative to the multi-screen origin.
This is equal to the true top edge, ignoring any OS UI element drawn at the top of the screen. Windows cannot be placed in those areas; to get the top coordinate of the screen area that windows can be placed in, use {{domxref("ScreenDetailed.availTop")}}.
[!NOTE] In Firefox, a non-standard implementation of the
topproperty is available on theScreeninterface. See the Non-standard example below for usage details, and see theScreenreference page for browser support information relating to the non-standard implementation.
A number.
// Available in browsers that support the Window Management API
const screenDetails = await window.getScreenDetails();
// Return the absolute top value of the first screen
const screen1Top = screenDetails.screens[0].top;
// Available in Firefox
// Return the absolute top value of the current screen
const screenTop = window.screen.top;
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