2.2.1 [HTML] Section 6.2, SGML basic types


The specification states:

 CDATA is a sequence of characters from the document character set and may include 
 character entities. User agents should interpret attribute values as follows:
 - Replace character entities with characters,
 - Ignore line feeds,
 - Replace each carriage return or tab with a single space.

All Document Modes (Internet Explorer 7 and Internet Explorer 8)

Tabs and carriage returns are not replaced with a single space in CDATA content. Tabs are removed but carriage returns are not removed.

All Document Modes (Internet Explorer 9)

Tabs and carriage returns are not removed in CDATA content.

IE10 Mode and IE11 Mode (All Versions)

CRLF characters are replaced with an LF character.


The specification states:

 The first occurrence of the character sequence "</" (end-tag open delimiter) is 
 treated as terminating the end of the element's content. In valid documents, this 
 would be the end tag for the element.

All Document Modes (All Versions)

The end-tag open delimiter (</) sequence is sufficient to terminate the element's content only if it is part of the end tag of the element. If only the character sequence is given (without the rest of the closing tag), subsequent content will be consumed until the next tag close (>) delimiter. It is not the character sequence that terminates the content of an element, but the entire end tag.


The specification states:

 ID and NAME tokens must begin with a letter ([A-Za-z]) and may be followed by any 
 number of letters, digits ([0-9]), hyphens ("-"), underscores ("_"), colons (":"), 
 and periods (".").

All Document Modes (All Versions)

The following clarifications apply:

  • ID and NAME tokens do not need to start with A-Za-z. These tokens can start with digits, hyphens, underscores, colons and periods. Additionally, the NAME token can start with or contain non-ASCII characters.

  • The ID token can start with or contain a non-ASCII character.


The specification states:

 NUMBER tokens must contain at least one digit ([0-9])

All Document Modes (All Versions)

Requirements for the NUMBER token exceed those in the specification. Not only must a NUMBER token contain at least one digit, it must also represent a valid number and cannot contain letters of the alphabet. NUMBER tokens containing non-numeric characters are not valid NUMBER tokens because they are not valid numbers. As a result, the values are ignored and replaced with a default (such as 2147483647 for input maxlength).