It appears you changed the API you were using to QuotesOnDesign.com. Also, appears you are not getting the results you want. If you notice, you are only getting the same quote, no matter how many times you click on the New Quote button. That is because QuotesOnDesign.com caches the results, so you keep getting the same 6 quotes each time. To prevent caching, you must put the following code in the $(document).ready callback function, before you call getQuote.
There is really no reason to pull 6 quotes as you are doing with rand&filter[posts_per_page]=6 in the API url’s querystring, because you only need the one. You could just specify rand&filter[posts_per_page]=1 Plus, even if you pull the 6 results (which are already random), you could just pull the first one by:
randomQuote = data.content;
randomAuthor = "-"+data.title;