CSS and JavaScript in the Custom page

I am trying to use CSS and JavaScript in the Custom page, but it isn't working.:
The only coding format the Custom page supports is HTML.
If you prefer to use JavaScript, you'll have to do so via the Modules page. To do so, please go to your account and click Developers Portal, then click on
API Reference where you will see the modules we offer.
Of course you can also create your own modules by going to the My Modules tab, where you will be able to upload your own module code. Kindly note that we currently offer up to four Module pages per app.
Please note that none of the other app pages will support JavaScript.
One last thing: Make sure you use the correct path for the MobileAppApi: <script type="text/javascript" charset="utf-8" src="http://api.mobile.conduit-services.com/MobileAppApi"></script>