What is the difference between single and double slash in Xpath

 /

1.  start selection from the document node
2. allows you to create 'absolute' path expressions
3. e.g. “/html/body/p” matches all the paragraph elements

 //

4.  start selection matching anywhere in the document 
5. allows you to create 'relative' path expressions
6. e.g. “//p” matches all the paragraph elements