Each HTML file consists of three parts: the document type definition, the head, and the body. While the body contains everything that the browser is supposed to display, “header data,” i.e. meta-information about the document is located in the head. These describe the body content, summarize it and refer to other sources or relationships with other documents.

Important SEO elements in the HTML header[edit]

There are countless possible elements in the HTML header with more or less widespread sorts of information. The following are important for search engine optimization:

  • Meta Title: The title tag defines the entire page and is displayed in the Google search results. It should not exceed the maximum length of 70 characters. The interpretation of title tags has changed, however, through various Google updates. Tests have shown that a fixed number of characters no longer determines whether a title is truncated. Instead, Google calculates the pixel width of each character and adds it up to a total width. When these pixel width exceeds the maximum, the title is truncated and “...” gets appended. Furthermore, it is recommended to integrate the main keyword of the page in the meta title.
  • Meta Description: This description should be no longer than 175 characters, contain the keyword and have advertising character since it will appear in the Google search results.
  • Meta Keyword: Not really used by search engines any more.
  • Meta Robots: Indicates to the crawler how to deal with the specific page. Possible values ​​are noindex, where indexing is prohibited and a follow/nofollow element for controlling whether the links on page should or should not be followed.

Output in the SERPs[edit]

Some of the listed information, in particular the meta title and meta description, will be shown in the results of search engines. The meta title is output as the first line of a result and should spark curiosity to make users aware of it. The meta description is displayed below the link to the website. If it contains your search term, it will be displayed in bold. Therefore, it is important to accommodate the main keywords in the description. An appealing formulation that prompts you to click is useful at this point to prompt the desired user action.

The meta title also appears at another place. If you open a page in the browser, then the meta title is displayed either in the top status bar, or in more recent versions it’s the name on the individual tab depending on the browser and version. In the latter variation, it is important that the first 25 to 30 characters are meaningful since the tab label usually cannot display the entire title.

Possible errors in the head[edit]

It is important that title tag and meta description exists only once for any webpage. Meta information like canonical tag and meta robots should be adjusted to the specifications in the XML Sitemap, the Robots.txt, and in the .htaccess.

The meta keyword is indeed not used much anymore for the assessment of websites and their ranking, it should not be misused for keyword spam. If the meta keyword is being maintained, one to three entries suffice completely. If it is a niche website, up to six keywords may be justified.

Relevance to search engine optimization[edit]

The information in the head of a website are extremely important for search engine optimization. Failure to provide a meta description or filling it up with duplicate content is one of the most serious mistakes in search engine optimization. Meta data is a way to accommodate additional content for online stores. You will need the canonical tag to avoid duplicate content, for example, if one website is represented by multiple URLs, or if content has been cited with permission from other websites. The meta robots are used in the head section, to let Google know which sub-pages should be indexed on a website and which ones should not be. This is particularly important to make the best utilization of the crawl budget of a website.

In order for certain types of data to be executed at the client or on the server with the appropriate application, the respective MIME type should ideally be specified in the header of the document.