The Microsoft Edge team has proposed a native Split Screen API that allows opening a URL side-by-side using the _split target:

// Target behavior: opens the URL in a split-screen pane window.open("https://example.com", "_split");

In browsers where this isn't supported, _split is treated as a standard named window, opening a new tab instead of a split pane. I need to implement a fallback (e.g., an internal iframe layout) only when the native feature is unavailable.

I've searched navigator.userAgent and window properties but haven't found a reliable flag for this specific API support.

Is there a way to programmatically detect if the browser supports the _split window target?

Simon Stnn's user avatar

Per the explainer you linked to a new navigator.splitTabSupported boolean is supposed to be added.
You should be able to check for its presence to know whether that value is supported by the UA or not.

console.log("knows about split tab?", "splitTabSupported" in navigator); console.log("currently supported", !!navigator.splitTabSupported);

Note that both checks don't do the same, since when an UA knows about _split, but doesn't support it in the current context, it should treat it as _blank.

Kaiido's user avatar

Scroll down a bit further right on that page you linked to, it says:

Adding a splitTabSupported property to the Navigator object. navigator.splitTabSupported returns a Boolean value indicating whether the browser supports a virtual split screen configuration or not.

Example:
if (navigator.splitTabSupported) {
// The browser does support split tab feature.
}

C3roe's user avatar

1 Comment

Checking the returned value doesn't suffice for OP's scenario though. This property could return false when it does support the feature but doesn't allow it in the current context, in which case it would fallback to _blank, instead of a window named "_split" in browsers that simply don't support the feature.

2026-04-15T07:35:25.12Z+00:00

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