What programming language to use to create data visualization on website and to push the data in a downloadable report?

I work with a team that need to create a online tool that would allow people to take some kind of survey and then to instantly get their results in a visual way (spider charts, pie charts, etc...), and to download a pdf with those results.

And we have no idea what language should be used to create such a system on a webplatform. Anyone could put us on the right tracks ?

Thank you for your time!