Wrap with an <a> element all the '#tag' occurrences in a string. Usefull for twitter json.

test_if_hashtag.js

function test_if_hashtag(string) {
  var thestring=string;
  var pattern = /#([a-zA-Z0-9]+)/g;
  return thestring.replace(pattern, "<a href='https://twitter.com/search?q=%23$1' target='_blank'>#$1</a>");
}