I’m not sure what they were going for, but I know that modern browsers do just in time compilation for regularly repeated code parts to allow much faster execution, so “interpreted programming language” may be a little of a blurry definition. See https://developer.mozilla.org/en-US/docs/Glossary/Just_In_Time_Compilation

I couldn’t find any info on any hardware specific to JS/JSON for clients but I’m no expert, maybe they will provide more info.