How can i find the name of this spider?

it has a black body with long legs. The legs are orange and at the joints it has a black colour. Its pretty big. Its backside is decorated with small white dots and the part where the legs start it is yellow. The top portion of the backside is orange. Can anyone please give me the name of this spider. I found it in a garden. Or is there any site where i can upload a photo and we get the name of that animal?