Unique By HTTP-EQUIV and NAME

Every META element is imported from the resource document to the Master Page and will overwrite the CONTENT of every META element with an identical HTTP-EQUIV or NAME attribute value, if present. There is no cross-over between HTTP-EQUIV and NAME attribute values, so a (fictional) HTTP-EQUIV attribute value of "status" won't affect another META element with a NAME attribute value of "status". Any META elements in a resource document that are not already present in the Master Page are appended to the end of the Master Page's HEAD tag for the merged document. All META elements in the Master Page that are not present in the resource document are left intact and unchanged.

As with HTML Master Page's handling of the TITLE tag, this handling of META elements also propagates along a chain of Master Pages except that CONTENT values closest to the requested resource document override those with the same HTTP-EQUIV or NAME attribute value that are further away in the chain.

Examples

Resource document specifies that it is not to be indexed and its links are not to be followed by robots while its Master Page allows both (remember that settings in the resource document always prevail over contradicting settings in its Master Page and any chained Master Pages thereafter):
```
<meta name="robots" content="NOINDEX,NOFOLLOW">
+ <meta name="robots" content="INDEX,FOLLOW">
= <meta name="robots" content="NOINDEX,NOFOLLOW">
```

Resource document has no META element for a description of the page's content while its Master Page provides a default value (which -- we hope -- is truly relevant to every resource document that is subordinate to the specified Master Page):

(nothing)
+ <meta name="description" content="This probably over-reaching description had better say something useful about every page that will inherit it!">
= <meta name="description" content="This probably over-reaching description had better say something useful about every page that will inherit it!">

Resource document specifies its author while its Master Page has no META element with the same NAME value ("author"):

<meta name="author" content="William W. Kimball, Jr., M.B.A., M.S.I.S.">
+ (nothing)
= <meta name="author" content="William W. Kimball, Jr., M.B.A., M.S.I.S.">