files/en-us/web/api/screendetailed/availtop/index.md
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The availTop read-only property of the
{{domxref("ScreenDetailed")}} interface is a number representing the y-coordinate (top edge) of the available screen area inside the OS virtual screen arrangement, relative to the multi-screen origin.
This is equal to the {{domxref("ScreenDetailed.top")}} property, plus the height of any OS UI element drawn at the top of the screen. Windows cannot be placed in those areas, so availTop is useful for giving you the top boundary of the actual area available to open or place windows.
[!NOTE] A non-standard implementation of the
availTopproperty is available on theScreeninterface in all browsers. 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 availTop value of the first screen
const screen1AvailTop = screenDetails.screens[0].availTop;
// Available in all browsers
// Return the availTop value of the current screen
const screenAvailTop = window.screen.availTop;
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