How do I avoid cross site errors when using the google web store API?
I'm trying to follow this simple examples given in the google web store API docs. 
Unfortunately their minimal PHP example contains a lot of stuff I dont need (and dont have setup).

So I'm looking at hardcoding the basic stuff into the HTML file, just to get communication with the google servers working:

My code looks like this:

    <html>
      <head>
      </head>
      <body>
        <script type="text/javascript" src="https://www.google.com/jsapi"></script>
    	<script type="text/javascript">
    	  purchase = function() { console.log("Old purchase function"); }
    	    generatedJwt = "..."; // I use a real JWT here....
    	    google.load('payments', '1.0', {
    	      'packages': ['sandbox_config'],
    	      callback: function()
    	      {
    	        //Success handler
    	        var successHandler = function(purchaseAction){
    	          if (window.console != undefined) {
    	            console.log("Purchase completed successfully.",purchaseAction);
    	       }
    	      }
    
    	      //Failure handler
              var failureHandler = function(purchaseActionError)
              {
    	         if (window.console != undefined)
                 {
    		    console.log("Purchase did not complete.", purchaseActionError);
    		 }
    	       }
    
    	       var purchase = function()
               {
    		  goog.payments.inapp.buy({
    	             'jwt'     : generatedJwt,
    	             'success' : successHandler,
    	             'failure' : failureHandler
                  });
               }
            }
          });
       </script>
       <button class="buy-button" id="buybutton1" name="buy" type="button" onClick="purchase()">
          Buy
       </button>
     </body>
   </html>


When I click on the buy button I get an error message pop up from google, and the following error in the console:

    Unsafe JavaScript attempt to access frame with URL   
    http://localhost/google_iap/buy_page.html 
    from frame with URL
    https://sandbox.google.com/checkout/inapp/static/gwt/payments.html?viewportScreenCenterX=-857.5&viewportScreenCenterY=611#id=I1_1324454042050&parent=http%3A%2F%2Flocalhost&rpctoken=166967692&_methods=onPurchaseActionStatus%2CgetJwt%2C_ready%2C_close%2C_open%2C_resizeMe.
    Domains, protocols and ports must match.

What do I need to do to make this simple example work?
How do I avoid cross site errors when using the google web store API?
===

I'm trying to follow this simple examples given in the google web store API docs. 
Unfortunately their minimal PHP example contains a lot of stuff I dont need (and dont have setup).

So I'm looking at hardcoding the basic stuff into the HTML file, just to get communication with the google servers working:

My code looks like this:

    <html>
      <head>
      </head>
      <body>
        <script type="text/javascript" src="https://www.google.com/jsapi"></script>
    	<script type="text/javascript">
    	  purchase = function() { console.log("Old purchase function"); }
    	    generatedJwt = "..."; // I use a real JWT here....
    	    google.load('payments', '1.0', {
    	      'packages': ['sandbox_config'],
    	      callback: function()
    	      {
    	        //Success handler
    	        var successHandler = function(purchaseAction){
    	          if (window.console != undefined) {
    	            console.log("Purchase completed successfully.",purchaseAction);
    	       }
    	      }
    
    	      //Failure handler
              var failureHandler = function(purchaseActionError)
              {
    	         if (window.console != undefined)
                 {
    		    console.log("Purchase did not complete.", purchaseActionError);
    		 }
    	       }
    
    	       var purchase = function()
               {
    		  goog.payments.inapp.buy({
    	             'jwt'     : generatedJwt,
    	             'success' : successHandler,
    	             'failure' : failureHandler
                  });
               }
            }
          });
       </script>
       <button class="buy-button" id="buybutton1" name="buy" type="button" onClick="purchase()">
          Buy
       </button>
     </body>
   </html>


When I click on the buy button I get an error message pop up from google, and the following error in the console:

    Unsafe JavaScript attempt to access frame with URL   
    http://localhost/google_iap/buy_page.html 
    from frame with URL
    https://sandbox.google.com/checkout/inapp/static/gwt/payments.html?viewportScreenCenterX=-857.5&viewportScreenCenterY=611#id=I1_1324454042050&parent=http%3A%2F%2Flocalhost&rpctoken=166967692&_methods=onPurchaseActionStatus%2CgetJwt%2C_ready%2C_close%2C_open%2C_resizeMe.
    Domains, protocols and ports must match.

What do I need to do to make this simple example work?