What Is an Ajax PageRank (PR) Checker Script? Google PageRank is a measure of importance of a webpage, which is determined by Google. PageRank is calculated using a complex algorism, which takes a huge variety of factors into account. PageRank is one of the factors that determines the SERP ranking of a webpage. How Do I Install This Script? Installing this script takes less than 5 minutes! Just unzip the contents of the file and upload them to either your root directory, or a sub-directory.