Operation of node attributes jQuery

1, attr () is used to read or set properties 
   - passing a parameter to read the property 
   - property passed two parameters 
Note: The value no matter how many elements are found only returns the first element attribute nodes specified 
      but will all the value of an attribute node elements are set to the specified value 
      if the property node set does not exist, then all of the elements will be found to add the attribute node

 

 2, prop () method