Google’s John Mueller Warns Against Custom Elements In Head

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oogle’s Search Advocate, John Mueller, has issued a warning regarding the use of custom elements in the <head> section of web pages. Custom elements, which are part of the Web Components specifications, allow developers to create HTML elements tailored to their specific requirements. These custom tags enable the creation of reusable and self-contained HTML elements that operate independently from the rest of the code. However, a recent Twitter discussion raised questions about the validity of placing custom elements in the <head> section.

Mueller has expressed concerns that using custom elements in the <head> can disrupt Google’s rendering and indexing process, potentially leading to negative consequences for SEO. He explains that if there are other essential meta tags, such as «robots noindex,» positioned below the custom elements that should be in the <head>, Google may fail to recognize them during rendering.

To better comprehend Mueller’s statement, it’s important to understand how Google renders web pages. The HTML of a web page can be likened to a recipe, with resources like CSS, JavaScript, images, and videos serving as ingredients. The rendering process is akin to cooking, where the recipe is transformed into the final product visible to users in their browsers. When Google’s crawler retrieves the HTML, the rendering process begins by interpreting the code and assembling the necessary resources to display the web page visually.

The implications of custom HTML tags on SEO should not be overlooked, despite their benefits for developers. Custom tags can impact SEO because search engines, including Google, typically rely on standard HTML tags to comprehend a page’s content and structure. For instance, if a custom element is used in the <head>, Google may fail to recognize subsequent standard tags during rendering. Consequently, this could result in Google overlooking crucial meta tags that are relevant to SEO.

While custom HTML tags offer flexibility, there are valid reasons to exercise caution when using them. Mueller’s concerns aside, compatibility issues may arise with older browsers and screen readers. Additionally, clashes within the global namespace and concerns regarding the separation of functionality, meaning, and presentation are potential drawbacks.

Fortunately, there is an alternative approach in the form of JSON-LD tags for those seeking to enhance SEO while retaining the advantages of custom tags. JSON-LD, or JavaScript Object Notation for Linked Data, provides a means of encoding Linked Data using JSON. When properly structured, this data can be incorporated into a <script> tag of type «application/ld+json» to provide structured metadata about the page. By doing so, search engines find it easier to interpret the content, thereby increasing the likelihood of the page ranking prominently in relevant search results.

In conclusion, although web development continues to evolve with exciting new tools, the impact of custom HTML tags on SEO is an ongoing area of exploration. Those who have concerns about compatibility or SEO-related issues may opt for standard HTML tags or consider using JSON-LD as alternative approaches.