diff --git a/unpacked/MathJax.js b/unpacked/MathJax.js
index 48a11c40c..2214b23d9 100644
--- a/unpacked/MathJax.js
+++ b/unpacked/MathJax.js
@@ -3075,8 +3075,8 @@ MathJax.Hub.Startup = {
     isMac:       (navigator.platform.substr(0,3) === "Mac"),
     isPC:        (navigator.platform.substr(0,3) === "Win"),
     isMSIE:      ("ActiveXObject" in window && "clipboardData" in window),
-    isFirefox:   (AGENT.match(/Gecko\//) && !AGENT.match(/like Gecko/)),
-    isSafari:    (AGENT.match(/ (Apple)?WebKit\//) != null &&
+    isFirefox:   (!!AGENT.match(/Gecko\//) && !AGENT.match(/like Gecko/)),
+    isSafari:    (!!AGENT.match(/ (Apple)?WebKit\//) && !AGENT.match(/ like iPhone /) &&
                      (!window.chrome || window.chrome.loadTimes == null)),
     isChrome:    (window.chrome != null && window.chrome.loadTimes != null),
     isOpera:     (window.opera != null && window.opera.version != null),