Sample of taking some text and extracting tokens wrapped in {{ }} with regex. JSFiddle: http://jsfiddle.net/2c5LC/2/

gistfile1.js

var mail = "this is a mail with some {{special}} strings. Some of these {{special}} strings should be replaced with a {{someValue}}."
  
var pattern = /\{\{([\w]*)\}\}/g;
var match;
while((match = pattern.exec(mail)) !==null){
    console.log(match);
    console.log('match: ' + match[0] + ' at index :' + match.index);
    console.log('capture: ' + match[1]);
}