You cannot run Node.JS on Firefox. The marked answer is incorrect. Node.JS itself does not run on browsers or mobile devices. JXcore , the mobile and integrated Node.JS distribution, runs on iOS and Android. It does not currently work on Firefox OS.
Actually there is no technical bottleneck due to which JXcore does not work in Firefox. JXcore embeds SpiderMonkey in addition to the V8. The problem is that Firefox OS does not allow the use of native code.
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