Secret copy to clipboard JavaScript function in Chrome and Firefox?

Update

Looks like browsers are starting to support copy natively in JS

In the console windows of both Chrome and Firefox on Mac I can execute

copy("party in your clipboard!");

and the text gets copied to my clipboard. I have searched SO and Google and can't seem to find anything on this.

• Are these specific to each browser?
• Where can I find more information on these JavaScript functions?

Browser versions:

JavaScript returned from Chrome console when executing 'copy'

function (object)
    {
        if (injectedScript._type(object) === "node") {
            var nodeId = InjectedScriptHost.pushNodePathToFrontend(object, false, false);
            InjectedScriptHost.copyNode(nodeId);
        } else
            InjectedScriptHost.copyText(object);
    }

• What does this code mean?

Here are 2 screenshots of executing copy function in Chrome console with all chrome extensions disabled