Why do Envato Marketplace have utf8=✓ in their search url's

On all of the Envato Market places like AudioJungle, ActiveDen and GraphicRiver.

When you use the search bar the url it goes to contains utf8=✓

http://audiojungle.net/search?utf8=✓&term=dfg ifacetimeapp

  1. Why do they need to declare the charset?
  2. Why would they use a tick instead of true or 1 ?
  3. I would expect ✓ to be less browser safe?


Hope you will get answer here.