Is this spider poisoness?

Question

I live in China and there is a very big spider outside the window. Its legs are going out at four corners and it has a big body with three yellow stripes going across it. It seems a bit over an inch in length. Plus there are sort of white zig zags on its web going out from it's legs and it has a small leafy looking sack on it's web. I don't know if I should be worried about it being dangerous. HELP!

Answer 1

It sounds like a St. Andrews Cross Spider.  (See photos here to compare: http://hvbackyard.blogspot.com/2007/11/3...  They are normally found in Australia though.  

But, they are harmless to humans, so don't worry!

Answer 2

http://www.whalecall.org/gallery/d/984-2...  This is a saint andrews cross spider  

Answer 3

It sounds like a member of the Orb Weaving spider Family Araneidae. The genus would be Argiope.

They are extremely beneficial and harmless. It's not dangerous at all, so sit back and enjoy watching it- they're very cool! :)