Enter WebVR mode with via external Javascript function

I'm programming 360 Tours with an custom overlay.
What I do is I call JS functions to load the scenes by JavaScript and that works great.

krpano.call("loadscene(scene_IMG_0013_Panorama_(1), null, MERGE, BLEND(1)););");

Now with this new WebVR function I want to enter the WebVR mode (and exit) via an DIV button.

But I have a problem with loading the WebVR and get 'webvr is not defined' when I want to call the 'webvr' instance.

I know that I can only call this instance when it's loaded and ready, but what I try I won't be able to
get it working. I tried it in the Document Ready or in de plugin attributes 'onavailable'. Nothing is working.

My question. Can I build a 'startWebVR()' function and call this by click on the DIV?

Thanks for your reply. Sounds good, and I tried it right away...but I get an error.

krpano is not a function

I tried also:

krpano.call("webvr.enterVR();");

also an error.

I have an function to toggle the GYRO and that is working like this:

function switchGyro() {
	if(gyroOn === 0) {
		var krpano = document.getElementById('krpanoSWFObject');
		krpano.set("plugin[gyro].enabled", "true");
		$gyroOn = 1;
	} else {
		var krpano = document.getElementById('krpanoSWFObject');
		krpano.set("plugin[gyro].enabled", "false");
		$gyroOn = 0;
	}
}

There I can use krpano.set...is this not possible with 'enterVR'?

Found a solution!

In the plugin setting there are two attributes:

plugin name="WebVR" keep="true" devices="html5"
	    	pluginurl="%SWFPATH%/plugins/webvr.js"
	    	url=""

I don't know why but the pluginurl is not working and loading the JS file, so I copied the link to URL attribute
and now the JS file is loaded..

Then I use this function now to toggle to EnterVR

function enterVR() {
	var krpano = document.getElementById('krpanoSWFObject');
	krpano.call("webvr.enterVR()");
}

and that is working...