title: How to get data for XMLHTTP requests using scrapy
body: <p>A web page where the data I am intersted in has some XHR requests. 
  I have got the url of the XHR request using developer tools.
  Now how to implement the same in my spider.py file and how to get all the values in that.I have started with scrapy unaware of working with ajax post requests as this. Please guide me on how to get the data and want the fields available to be stored in an excel file. </p>