The parameter data for this visual, encoded as JSON, provided by a router if this visual represents a navigation page.

When this value is set, the parameter can be accessed in JavaScript through the .Parameter property on this object.

Example:

<JavaScript>
    router.goto("profile", { id: 3 });
</JavaScript>
...
<Page ux:Name="profile">
    <JavaScript>
        profile.Parameter.onValueChanged(module, function(param) {
            // param holds the deserialized object { id: 3 }
        });
    </JavaScript>
</Page>