diff --git a/src/sys/es/fan/MimeType.js b/src/sys/es/fan/MimeType.js
index 9f766764e..cc6592183 100644
--- a/src/sys/es/fan/MimeType.js
+++ b/src/sys/es/fan/MimeType.js
@@ -89,13 +89,14 @@ class MimeType extends Obj {
   static #doParseParams(s, offset) {
     const params = Map.make(Str.type$, Str.type$);
     params.caseInsensitive(true);
+    let len      = s.length;
     let inQuotes = false;
     let keyStart = offset;
     let valStart = -1;
     let valEnd   = -1;
     let eq       = -1;
     let hasEsc   = false;
-    for (let i=keyStart; i<s.length; ++i) {
+    for (let i=keyStart; i<len; ++i) {
       let c = s.charAt(i);
 
       // let parens slide since sometimes they occur in cookies
@@ -104,10 +105,12 @@ class MimeType extends Obj {
 
       if (c == '=' && eq < 0 && !inQuotes) {
         eq = i++;
-        while (MimeType.#isSpace(s, i)) ++i;
+        while (i<len && MimeType.#isSpace(s, i)) ++i;
+        if (i >= len) break;
         if (s.charAt(i) == '"') { inQuotes = true; ++i; c = s.charAt(i); }
         else inQuotes = false;
         valStart = i;
+        c = s.charAt(i);
       }
 
       if (c == ';' && eq < 0 && !inQuotes) {
@@ -145,13 +148,14 @@ class MimeType extends Obj {
       }
     }
 
-    if (keyStart < s.length) {
-      if (valEnd < 0) valEnd = s.length-1;
+    if (keyStart < len) {
       if (eq < 0) {
-        var key = Str.trim(s.slice(keyStart, s.length));
+        var key = Str.trim(s.slice(keyStart, len));
         params.set(key, "");
       }
       else {
+        if (valStart < 0) valStart = eq+1;
+        if (valEnd < 0) valEnd = len-1;
         let key = Str.trim(s.slice(keyStart, eq));
         let val = Str.trim(s.slice(valStart, valEnd+1));
         if (hasEsc) val = MimeType.#unescape(val);
diff --git a/src/sys/java/fan/sys/MimeType.java b/src/sys/java/fan/sys/MimeType.java
index a055c2f31..9b64c3002 100644
--- a/src/sys/java/fan/sys/MimeType.java
+++ b/src/sys/java/fan/sys/MimeType.java
@@ -110,13 +110,15 @@ private static Map doParseParams(String s, int offset)
   {
     Map params = new Map(Sys.StrType, Sys.StrType);
     params.caseInsensitive(true);
+    int len = s.length();
     boolean inQuotes = false;
     int keyStart = offset;
     int valStart = -1;
     int valEnd   = -1;
     int eq       = -1;
     boolean hasEsc = false;
-    for (int i = keyStart; i<s.length(); ++i)
+
+    for (int i = keyStart; i<len; ++i)
     {
       int c = s.charAt(i);
 
@@ -127,10 +129,12 @@ private static Map doParseParams(String s, int offset)
       if (c == '=' && !inQuotes && valStart < 0)
       {
         eq = i++;
-        while (FanInt.isSpace(s.charAt(i))) ++i;
+        while (i<len && FanInt.isSpace(s.charAt(i))) ++i;
+        if (i >= len) break;
         if (s.charAt(i) == '"') { inQuotes = true; ++i; c=s.charAt(i); }
         else inQuotes = false;
         valStart = i;
+        c = s.charAt(i);
       }
 
       if (c == ';' && eq < 0 && !inQuotes)
@@ -172,16 +176,17 @@ private static Map doParseParams(String s, int offset)
       }
     }
 
-    if (keyStart < s.length())
+    if (keyStart < len)
     {
-      if (valEnd < 0) valEnd = s.length()-1;
       if (eq < 0)
       {
-        String key = s.substring(keyStart, s.length()).trim();
+        String key = s.substring(keyStart, len).trim();
         params.set(key, "");
       }
       else
       {
+        if (valStart < 0) valStart = eq+1;
+        if (valEnd < 0) valEnd = len-1;
         String key = s.substring(keyStart, eq).trim();
         String val = s.substring(valStart, valEnd+1).trim();
         if (hasEsc) val = unescape(val);
@@ -338,4 +343,5 @@ static Map emptyParams()
   private Map params;
   private String str;
 
-}
\ No newline at end of file
+}
+
diff --git a/src/sys/js/fan/MimeType.js b/src/sys/js/fan/MimeType.js
index e31e7c093..08b18f1ee 100644
--- a/src/sys/js/fan/MimeType.js
+++ b/src/sys/js/fan/MimeType.js
@@ -79,13 +79,14 @@ fan.sys.MimeType.doParseParams = function(s, offset)
 {
   var params = fan.sys.Map.make(fan.sys.Str.$type, fan.sys.Str.$type);
   params.caseInsensitive$(true);
+  var len      = s.length;
   var inQuotes = false;
   var keyStart = offset;
   var valStart = -1;
   var valEnd   = -1;
   var eq       = -1;
   var hasEsc   = false;
-  for (var i=keyStart; i<s.length; ++i)
+  for (var i=keyStart; i<len; ++i)
   {
     var c = s.charAt(i);
 
@@ -96,10 +97,12 @@ fan.sys.MimeType.doParseParams = function(s, offset)
     if (c == '=' && eq < 0 && !inQuotes)
     {
       eq = i++;
-      while (fan.sys.MimeType.isSpace(s, i)) ++i;
+      while (i<len && fan.sys.MimeType.isSpace(s, i)) ++i;
+      if (i >= len) break;
       if (s.charAt(i) == '"') { inQuotes = true; ++i; c = s.charAt(i); }
       else inQuotes = false;
       valStart = i;
+      c = s.charAt(i);
     }
 
     if (c == ';' && eq < 0 && !inQuotes)
@@ -141,19 +144,20 @@ fan.sys.MimeType.doParseParams = function(s, offset)
     }
   }
 
-  if (keyStart < s.length)
+  if (keyStart < len)
   {
-    if (valEnd < 0) valEnd = s.length-1;
     if (eq < 0)
     {
-      var key = fan.sys.Str.trim(s.substring(keyStart, s.length));
+      var key = fan.sys.Str.trim(s.substring(keyStart, len));
       params.set(key, "");
     }
     else
     {
+      if (valStart < 0) valStart = eq+1;
+      if (valEnd < 0) valEnd = len-1;
       var key = fan.sys.Str.trim(s.substring(keyStart, eq));
       var val = fan.sys.Str.trim(s.substring(valStart, valEnd+1));
-      if (hasEsc) val = fan.sys.MimeType.unscape(val);
+      if (hasEsc) val = fan.sys.MimeType.unescape(val);
       params.set(key, val);
     }
   }
@@ -313,4 +317,5 @@ fan.sys.MimeType.predefined = function(media, sub, params)
 // Static Fields
 //////////////////////////////////////////////////////////////////////////
 
-// see sysPod.js
\ No newline at end of file
+// see sysPod.js
+
diff --git a/src/testSys/fan/MimeTypeTest.fan b/src/testSys/fan/MimeTypeTest.fan
index 1b03d25fc..287a2bd8a 100644
--- a/src/testSys/fan/MimeTypeTest.fan
+++ b/src/testSys/fan/MimeTypeTest.fan
@@ -92,7 +92,6 @@ class MimeTypeTest : Test
     verifyFromStr("a/b; charset=foo (comment)", "a", "b", ["charset":"foo (comment)"])
 
     verifyFromStrBad("foo")
-    verifyFromStrBad("a/b; x=")
   }
 
   Void verifyFromStr(Str s, Str media, Str sub, [Str:Str]? params)
@@ -141,6 +140,17 @@ class MimeTypeTest : Test
     verifyParseParams("a=b; c", ["a":"b", "c":""])
     verifyParseParams("a=b; cx", ["a":"b", "cx":""])
 
+    // not sure this is valid to have empty string; but have seen
+    // Safari send cookies like this
+    verifyParseParams("a=",     ["a":""])
+    verifyParseParams("a =",    ["a":""])
+    verifyParseParams("a= ",    ["a":""])
+    verifyParseParams("a  =  ", ["a":""])
+    verifyParseParams("a=; b=foo", ["a":"", "b":"foo"])
+    verifyParseParams("a=foo; b=", ["a":"foo", "b":""])
+    verifyParseParams("a=foo; b=; c=bar",          ["a":"foo", "b":"", "c":"bar"])
+    verifyParseParams("a = foo; b   = ; c =bar  ", ["a":"foo", "b":"", "c":"bar"])
+
     // not sure this is actually correctly formatted to have equals
     // in unquoted values, but have seen Chrome send cookies like this
     verifyParseParams("""a=sdecbc682; tz=America/New_York; b="05df13cc-9ef1"; c=MDI1MzE=; d=ABC=""",
@@ -149,15 +159,12 @@ class MimeTypeTest : Test
        "b":  "05df13cc-9ef1",
        "c":  "MDI1MzE=",
        "d":  "ABC="])
-
-    verifyEq(MimeType.parseParams("n=", false), null)
-    verifyErr(ParseErr#) { MimeType.parseParams("x=f;y=") }
   }
 
-  Void verifyParseParams(Str s, Str:Str params)
+  Void verifyParseParams(Str s, Str:Str expect)
   {
     p := MimeType.parseParams(s)
-    verifyEq(p, params)
+    verifyEq(p, expect)
     verifyEq(p.caseInsensitive, true)
   }
 
@@ -218,4 +225,5 @@ class MimeTypeTest : Test
     x := MimeType(s)
     verifyEq(x.isText, expect)
   }
-}
\ No newline at end of file
+}
+
diff --git a/src/web/test/CookieTest.fan b/src/web/test/CookieTest.fan
index c3ae141b1..67aebb085 100644
--- a/src/web/test/CookieTest.fan
+++ b/src/web/test/CookieTest.fan
@@ -22,6 +22,13 @@ class CookieTest : Test
        "VERSION-foo%2Fbar": "unspecified",
        "__u": "1303429918|un=(referral)|ud=referral"])
 
+    // test key=(no val)
+    s = "mm_testcookie_storage=; foobar=123; _ga_DGW3P9MPX4=GS1.2.1720526761"
+    verifyEq(MimeType.parseParams(s),
+      ["mm_testcookie_storage": "",
+       "foobar": "123",
+       "_ga_DGW3P9MPX4": "GS1.2.1720526761"])
+
     verifyCookie(Cookie("foo=bar"), Cookie("foo", "bar"))
     verifyCookie(Cookie("foo=\"bar baz\""), Cookie("foo", "\"bar baz\""))
     verifyCookie(Cookie("foo=\"_\\\"quot\\\"_\""), Cookie("foo", "\"_\\\"quot\\\"_\""))
@@ -68,4 +75,5 @@ class CookieTest : Test
     verifyEq(c.sameSite, "strict")
   }
 
-}
\ No newline at end of file
+}
+