If double slash (//) is used 2 times in XPath, what does it mean?

Question

What does a double-slash used twice in an XPath selector mean?

Suppose I'm using a path like:

//div[@id='add']//span[@id=addone'] 

Answer 1

A double slash "//" means any descendant node of the current node in the HTML tree which matches the locator.

A single slash "/" means a node which is a direct child of the current.

//div[@id='add']//span[@id=addone'] will match:

<div id="add">   <div>     <span id="addone">   </div> </div> 

And:

<div id="add">     <span id="addone"> </div> 

//div[@id='add']/span[@id=addone'] will match only the second HTML tree.

Answer 2

Double slash (//) is the descendant-or-self axis; it is short for /descendant-or-self::node()/.

In your example XPath:

//div[@id='add']//span[@id='addone'] 

• The first time // appears, it selects all div elements in the document with an id attribute value equal to 'add'.
• The second time // appears, it selects all span elements that are descendents of each of the div elements selected previously.
• Note that using two double slashes twice is different than just using double slash once. For example, //span[@id='addone'] would select all span elements with @id='addone' in the entire document, regardless of whether they are a descendent of a div with @id='add'.