getAllStyleSheets.js

function allStyleSheets(doc) {
  var stylesheets = [];
  for(var i = 0; i < doc.styleSheets.length; i++)
    stylesheets = stylesheets.concat(getStyleSheets(doc.styleSheets[i]));
  return stylesheets;
}

function getStyleSheets(stylesheet) {
  if(!stylesheet)
    return []; // Firefox protects against @import statement loops
  var stylesheets = [stylesheet];
  var rules = stylesheet.cssRules;
  for(var i = 0; i < rules.length; i++) {
    if(rules[i].type == CSSRule.IMPORT_RULE)
      stylesheets = stylesheets.concat(getStyleSheets(rules[i].styleSheet));
  }
  return stylesheets;
}