diff --git a/Libraries/LibWeb/Parser/HTMLTokenizer.cpp b/Libraries/LibWeb/Parser/HTMLTokenizer.cpp
index b0b1bfaab0..ba4df5d474 100644
--- a/Libraries/LibWeb/Parser/HTMLTokenizer.cpp
+++ b/Libraries/LibWeb/Parser/HTMLTokenizer.cpp
@@ -322,6 +322,317 @@ Optional<HTMLToken> HTMLTokenizer::next_token()
             END_STATE
 
             BEGIN_STATE(AfterDOCTYPEName)
+            {
+                ON_WHITESPACE
+                {
+                    continue;
+                }
+                ON('>')
+                {
+                    SWITCH_TO_AND_EMIT_CURRENT_TOKEN(Data);
+                }
+                ON_EOF
+                {
+                    TODO();
+                }
+                ANYTHING_ELSE
+                {
+                    if (toupper(current_input_character.value()) == 'P' && consume_next_if_match("UBLIC", CaseSensitivity::CaseInsensitive)) {
+                        SWITCH_TO(AfterDOCTYPEPublicKeyword);
+                    }
+                    if (toupper(current_input_character.value()) == 'S' && consume_next_if_match("YSTEM", CaseSensitivity::CaseInsensitive)) {
+                        SWITCH_TO(AfterDOCTYPESystemKeyword);
+                    }
+                    TODO();
+                }
+            }
+            END_STATE
+
+            BEGIN_STATE(AfterDOCTYPEPublicKeyword)
+            {
+                ON_WHITESPACE
+                {
+                    SWITCH_TO(BeforeDOCTYPEPublicIdentifier);
+                }
+                ON('"')
+                {
+                    TODO();
+                }
+                ON('\'')
+                {
+                    TODO();
+                }
+                ON('>')
+                {
+                    TODO();
+                }
+                ON_EOF
+                {
+                    TODO();
+                }
+                ANYTHING_ELSE
+                {
+                    TODO();
+                }
+            }
+            END_STATE
+
+            BEGIN_STATE(AfterDOCTYPESystemKeyword)
+            {
+                ON_WHITESPACE
+                {
+                    SWITCH_TO(BeforeDOCTYPESystemIdentifier);
+                }
+                ON('"')
+                {
+                    TODO();
+                }
+                ON('\'')
+                {
+                    TODO();
+                }
+                ON('>')
+                {
+                    TODO();
+                }
+                ON_EOF
+                {
+                    TODO();
+                }
+                ANYTHING_ELSE
+                {
+                    TODO();
+                }
+            }
+            END_STATE
+
+            BEGIN_STATE(BeforeDOCTYPEPublicIdentifier)
+            {
+                ON_WHITESPACE
+                {
+                    continue;
+                }
+                ON('"')
+                {
+                    m_current_token.m_doctype.public_identifier.clear();
+                    SWITCH_TO(DOCTYPEPublicIdentifierDoubleQuoted);
+                }
+                ON('\'')
+                {
+                    m_current_token.m_doctype.public_identifier.clear();
+                    SWITCH_TO(DOCTYPEPublicIdentifierSingleQuoted);
+                }
+                ON('>')
+                {
+                    TODO();
+                }
+                ON_EOF
+                {
+                    TODO();
+                }
+                ANYTHING_ELSE
+                {
+                    TODO();
+                }
+            }
+            END_STATE
+
+            BEGIN_STATE(BeforeDOCTYPESystemIdentifier)
+            {
+                ON_WHITESPACE
+                {
+                    continue;
+                }
+                ON('"')
+                {
+                    m_current_token.m_doctype.system_identifier.clear();
+                    SWITCH_TO(DOCTYPESystemIdentifierDoubleQuoted);
+                }
+                ON('\'')
+                {
+                    m_current_token.m_doctype.system_identifier.clear();
+                    SWITCH_TO(DOCTYPESystemIdentifierSingleQuoted);
+                }
+                ON('>')
+                {
+                    TODO();
+                }
+                ON_EOF
+                {
+                    TODO();
+                }
+                ANYTHING_ELSE
+                {
+                    TODO();
+                }
+            }
+            END_STATE
+
+            BEGIN_STATE(DOCTYPEPublicIdentifierDoubleQuoted)
+            {
+                ON('"')
+                {
+                    SWITCH_TO(AfterDOCTYPEPublicIdentifier);
+                }
+                ON(0)
+                {
+                    TODO();
+                }
+                ON('>')
+                {
+                    TODO();
+                }
+                ON_EOF
+                {
+                    TODO();
+                }
+                ANYTHING_ELSE
+                {
+                    m_current_token.m_doctype.public_identifier.append(current_input_character.value());
+                    continue;
+                }
+            }
+            END_STATE
+
+            BEGIN_STATE(DOCTYPEPublicIdentifierSingleQuoted)
+            {
+                ON('\'')
+                {
+                    SWITCH_TO(AfterDOCTYPEPublicIdentifier);
+                }
+                ON(0)
+                {
+                    TODO();
+                }
+                ON('>')
+                {
+                    TODO();
+                }
+                ON_EOF
+                {
+                    TODO();
+                }
+                ANYTHING_ELSE
+                {
+                    m_current_token.m_doctype.public_identifier.append(current_input_character.value());
+                    continue;
+                }
+            }
+            END_STATE
+
+            BEGIN_STATE(DOCTYPESystemIdentifierDoubleQuoted)
+            {
+                ON('"')
+                {
+                    SWITCH_TO(AfterDOCTYPESystemIdentifier);
+                }
+                ON(0)
+                {
+                    TODO();
+                }
+                ON('>')
+                {
+                    TODO();
+                }
+                ON_EOF
+                {
+                    TODO();
+                }
+                ANYTHING_ELSE
+                {
+                    m_current_token.m_doctype.system_identifier.append(current_input_character.value());
+                    continue;
+                }
+            }
+            END_STATE
+
+            BEGIN_STATE(DOCTYPESystemIdentifierSingleQuoted)
+            {
+                ON('\'')
+                {
+                    SWITCH_TO(AfterDOCTYPESystemIdentifier);
+                }
+                ON(0)
+                {
+                    TODO();
+                }
+                ON('>')
+                {
+                    TODO();
+                }
+                ON_EOF
+                {
+                    TODO();
+                }
+                ANYTHING_ELSE
+                {
+                    m_current_token.m_doctype.system_identifier.append(current_input_character.value());
+                    continue;
+                }
+            }
+            END_STATE
+
+            BEGIN_STATE(AfterDOCTYPEPublicIdentifier)
+            {
+                ON_WHITESPACE
+                {
+                    SWITCH_TO(BetweenDOCTYPEPublicAndSystemIdentifiers);
+                }
+                ON('>')
+                {
+                    SWITCH_TO_AND_EMIT_CURRENT_TOKEN(Data);
+                }
+                ON('"')
+                {
+                    TODO();
+                }
+                ON('\'')
+                {
+                    TODO();
+                }
+                ON_EOF
+                {
+                    TODO();
+                }
+                ANYTHING_ELSE
+                {
+                    TODO();
+                }
+            }
+            END_STATE
+
+            BEGIN_STATE(BetweenDOCTYPEPublicAndSystemIdentifiers)
+            {
+                ON_WHITESPACE
+                {
+                    continue;
+                }
+                ON('>')
+                {
+                    SWITCH_TO_AND_EMIT_CURRENT_TOKEN(Data);
+                }
+                ON('"')
+                {
+                    m_current_token.m_doctype.system_identifier.clear();
+                    SWITCH_TO(DOCTYPESystemIdentifierDoubleQuoted);
+                }
+                ON('\'')
+                {
+                    m_current_token.m_doctype.system_identifier.clear();
+                    SWITCH_TO(DOCTYPESystemIdentifierSingleQuoted);
+                }
+                ON_EOF
+                {
+                    TODO();
+                }
+                ANYTHING_ELSE
+                {
+                    TODO();
+                }
+            }
+            END_STATE
+
+            BEGIN_STATE(AfterDOCTYPESystemIdentifier)
             {
                 ON_WHITESPACE
                 {