How does xpath works internally?

Generally we write xpath like using below formula

//tagname[@attributename=’attributevalue’]

But have you ever thought how it works internally and how it search for the element in the DOM?

In the below tutorial I have explained how does xpath works internally, please check it out and learn the basic concepts of xpath-

In this tutorial, I have used XPath Plugin SelectorsHub to explain the concept, you can download it from here.