How to add cordova in app browser plugin code inndex.html?

<script type="text/javascript" charset="utf-8">
	document.addEventListener("deviceready", onDeviceReady, false);
	function onDeviceReady() {
	 var ref = cordova.InAppBrowser.open('https://websitename.com/', '_blank', 'location=no,zoom=no,toolbar=no');
	}	
</script>