files/en-us/web/api/mediadevices/getsupportedconstraints/index.md
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The getSupportedConstraints() method of the {{domxref("MediaDevices")}} interface returns an object based on the {{domxref("MediaTrackSupportedConstraints")}} dictionary, whose member fields each specify one of the constrainable properties the {{Glossary("user agent")}} understands.
getSupportedConstraints()
None.
A new object based on the {{domxref("MediaTrackSupportedConstraints")}} dictionary listing the constraints supported by the user agent.
Because only constraints supported by the user agent are included in the list, each of these Boolean properties has the value true.
This example outputs a list of the constraints supported by your browser.
<p>The following media constraints are supported by your browser:</p>
<ul id="constraintList"></ul>
body {
font:
15px "Arial",
sans-serif;
}
const constraintList = document.querySelector("#constraintList");
const supportedConstraints = navigator.mediaDevices.getSupportedConstraints();
for (const constraint of Object.keys(supportedConstraints)) {
const elem = document.createElement("li");
elem.appendChild(document.createElement("code")).textContent = constraint;
constraintList.appendChild(elem);
}
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