function returnStringByUaType(desktop_content, mobile_content) {
  // iPad, should return 'desktop'
  // var ua_str = "Mozilla/5.0 (iPad; U; CPU OS 3_2_1 like Mac OS X; es-es) AppleWebKit/531.21.10 (KHTML, like Gecko) Mobile/7B405";
  // iPhone, should return 'mobile'
  // var ua_str = "Mozilla/5.0 (iPhone; U; CPU iPhone OS 3_0 like Mac OS X; en-us) AppleWebKit/528.18 (KHTML, like Gecko) Version/4.0 Mobile/7A341 Safari/528.16"

  var ua_str      = navigator.userAgent;
  var mobile_uas  = /palm|palmos|palmsource|blaz|blackberry|nokia|phone|midp|mobi|pda|wap|java|nokia|hand|symbian|chtml|wml|ericsson|lg|audiovox|motorola|samsung|sanyo|sharp|telit|tsm|mobile|mini|windows ce|smartphone|240x320|320x320|mobileexplorer|j2me|sgh|portable|sprint|vodafone|docomo|kddi|softbank|pdxgw|j-phone|astel|minimo|plucker|netfront|xiino|mot-v|mot-e|portalmmm|sagem|sie-s|sie-m|iphone|dream|ipod|android|320|webos|pie|blackberry|320x240/gi;
  
  // These 2 lines let you force desktop_content on the iPad, if that's what you want
  //var desktop_uas = /ipad/gi;
  //if(ua_str.match(mobile_uas) != null && ua_str.match(desktop_uas) == null) {
  
  if(ua_str.match(mobile_uas) != null) {
    return mobile_content;
  } else {
    return desktop_content;
  }
}