Is there a way to download the page using javascript/ajax functions except for jQuery? It is not an option.
If you are referring to downloading a html page served on another domain using ajax, then the answer is no. Due to security browsers does not allow that. Read more about that here: http://en.wikipedia.org/wiki/Same_origin_policy
You could probably solve this by using a service such as http://pipes.yahoo.com/pipes/ which uses CORS
Sure, use the ol' XMLHttpRequest.
It's possible using XMLHttpRequest if the page you're hitting is on the same domain. Just set the content type in the response to something like application/force-download.