Sadly the main problem here is that Webassembly itself is 32 bit for the time being. So you’d have to raise this issue with the World Wide Web Consortium and then convince every web browser to implement the updated spec 
Sadly the main problem here is that Webassembly itself is 32 bit for the time being. So you’d have to raise this issue with the World Wide Web Consortium and then convince every web browser to implement the updated spec