> <!*************SHIPPING INFO*********************> Your commenting is off. It should be:
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> if (cardChoice = false) You are assigning a value of false to cardChoice and then testing it, hence this condition would never be true irrespective of the value of cardChoice before. Maybe if(!cardChoice) is what you wanted to do.

> // STOP HIDING FROM INCOMPATIBLE BROWSERS -->
Not needed. Almost all modern browsers support javascript nowadays. If you still want to play it safe, use a <noscript> tag instead.

You are not using stylesheets which is a bad idea in itself. Separation of presentation, data and logic is crucial for todays' web apps. Also consider linking to an external script file.

Always use a validator to check the validity of the web pages you author. I would save both yours as well as the time of the person helping you out once it is known that the web page is a valid one. Consider keeping a DOCTYPE at the top of your page and validating against it using the online validator.