JavaScript SEO: How Google Search Indexes JavaScript Sites

Knowing the basics of JavaScript has become a vital skill for the modern SEO professional.

A modern SEO professional should also have a basic understanding of DOM (Document Object Model). You can think of DOM as a tool used by Google to explore and analyze web pages.

Basic Definitions

Before we get into best practices for optimizing JavaScript, let’s take a quick look at some basic terminology:

• JavaScript is a programming language used to make web pages dynamic and interactive. You can place JavaScript into an HTML document, or make a link or reference to it.
• HTML stands for Hypertext Markup Language. In simple words, it is a content organizer: HTML provides a website’s structure (bullet lists, headlines, subheadlines, paragraphs, etc.) and defines static content.
• AJAX is Asynchronous JavaScript and XML. Basically, it updates content without refreshing the whole page. AJAX enables web applications and servers to communicate without intruding on the current page.

Martin Splitt, a Google Webmaster Trends Analyst, explains how JavaScript influences SEO and how to optimize your JavaScript-powered website to be search-friendly.