gistfile1.js

var VideoCheckout = function() {
  
} 

VideoCheckout.prototype.init(videoId, {container, modalContainer, width, height}) {

  if(!modalContainer) {
    modalContainer = document.body
  }
  
}

VideoCheckout.prototype.openCheckoutModal(videoId) {
  // we need to create a modal on the parent page, put an iframe in it, 
  // and point the iframe to the video with a querystring of "checkoutModal".
  // We can then handle that query string in the embed code (in "scripts/embed/EmbedContainer")
  // and instead of showing the video, we can JUST show the checkout modal.
  
}

var video_checkout_9as8dfasdf = new VideoCheckout("videoId", {
  "container": document.querySelectorAll(".my-checkout-container")
  "width": 720,
  "height": 480
})

//************************************


In the actual video checkout code, in the action

...

showCheckoutWizard() {
  if(window.innerWidth < 800 && window.parent) {
    //we need to show the checkout outside of the window
    window.parent.video_checkout_9as8dfasdf.openCheckoutModal(window.videoId)
  }
}

...