diff --git a/lib/websocket/extensions/parser.rb b/lib/websocket/extensions/parser.rb
index f8d8891..ad65793 100644
--- a/lib/websocket/extensions/parser.rb
+++ b/lib/websocket/extensions/parser.rb
@@ -7,10 +7,11 @@ class Parser
       TOKEN    = /([!#\$%&'\*\+\-\.\^_`\|~0-9A-Za-z]+)/
       NOTOKEN  = /([^!#\$%&'\*\+\-\.\^_`\|~0-9A-Za-z])/
       QUOTED   = /"((?:\\[\x00-\x7f]|[^\x00-\x08\x0a-\x1f\x7f"\\])*)"/
-      PARAM    = %r{#{ TOKEN.source }(?:=(?:#{ TOKEN.source }|#{ QUOTED.source }))?}
-      EXT      = %r{#{ TOKEN.source }(?: *; *#{ PARAM.source })*}
-      EXT_LIST = %r{^#{ EXT.source }(?: *, *#{ EXT.source })*$}
-      NUMBER   = /^-?(0|[1-9][0-9]*)(\.[0-9]+)?$/
+      PARAM    = %r{#{ TOKEN.source }(?:[ \t]*=[ \t]*(?:#{ TOKEN.source }|#{ QUOTED.source }))?}
+      EXT      = %r{#{ TOKEN.source }(?:[ \t]*;[ \t]*#{ PARAM.source })*}
+      EXT_START = %r{[ \t]*#{ EXT.source }}
+      EXT_LIST = %r{\A[ \t]*#{ EXT.source }(?:[ \t]*,[ \t]*#{ EXT.source })*[ \t]*\z}
+      NUMBER   = /\A-?(0|[1-9][0-9]*)(\.[0-9]+)?\z/
 
       ParseError = Class.new(ArgumentError)
 
@@ -23,7 +24,7 @@ def self.parse_header(header)
         end
 
         scanner = StringScanner.new(header)
-        value   = scanner.scan(EXT)
+        value   = scanner.scan(EXT_START)
 
         until value.nil?
           params = value.scan(PARAM)
@@ -51,7 +52,7 @@ def self.parse_header(header)
 
           offers.push(name, offer)
 
-          scanner.scan(/ *, */)
+          scanner.skip(/[ \t]*,[ \t]*/)
           value = scanner.scan(EXT)
         end
         offers
diff --git a/spec/websocket/extensions/parser_spec.rb b/spec/websocket/extensions/parser_spec.rb
index 7458210..61904fa 100644
--- a/spec/websocket/extensions/parser_spec.rb
+++ b/spec/websocket/extensions/parser_spec.rb
@@ -24,6 +24,18 @@ def parse(string)
       ]
     end
 
+    it "parses HTTP whitespace around delimiters" do
+      expect(parse " \ta \t; mode \t= compress \t, other \t").to eq [
+        { :name => "a", :params => { "mode" => "compress" } },
+        { :name => "other", :params => {} }
+      ]
+    end
+
+    it "rejects input outside the complete header value" do
+      expect { parse "\na" }.to raise_error(WebSocket::Extensions::Parser::ParseError)
+      expect { parse "a\n" }.to raise_error(WebSocket::Extensions::Parser::ParseError)
+    end
+
     it "parses two offers with no params" do
       expect(parse 'a, b').to eq [
         { :name => "a", :params => {} }, { :name => "b", :params => {} }