What does the xmlns attribute do? [duplicate]

Answer 1

From the W3Schools:

the xmlns attribute specifies the xml namespace for a document.

This basically helps to avoid namespace conflicts between different xml documents, if for instance a developer mixes xml documents from different xml applications.

An example of this (also from the W3 website):

XML data to define an html table:

  

    
Apples
    
Bananas
  

XML data to define information about a coffee table

African Coffee Table80120

There are two table elements here, which would produce a conflict. To fix this, you can add a namespace to signify which piece of information defines an html table and which comprises information about a coffee table:

  
    Apples
    Bananas
  



  African Coffee Table
  80
  120