Explain why there are two runs for JavaScript

[hakanai]

JavaScript example given is:

$ time node src/main/javascript/java_faster_than_javascript.js 
node count: 13537
checksum: 470936697371

real    1m6,196s
user    1m13,707s
sys     0m2,256s
$ time node src/main/javascript/java_faster_than_node.js 
node count: 13537
checksum: 470936697371

real    0m26,172s
user    0m30,301s
sys     0m0,628s

What's the difference? Both are running on nodejs.

If it's just one is slower and one is faster, isn't keeping the faster one a better demonstration?