On: Do browsers parse javascript on every page load?

[erichocean]

JavaScript parsing speed is mostly a problem on mobile devices, not desktop browsers.

[nreece → erichocean]

  Google found that moving from a 10-result page loading in 
  0.4 seconds to a 30-result page loading in 0.9 seconds 
  decreased traffic and ad revenues by 20%. Tests at Amazon 
  revealed similar results: every 100ms increase in load time 
  of Amazon.com decreased sales by 1%.