How to add 3rd party widgets or html/javascript (ads) to blogger ?

sometimes it becomes necessary to add your own html/javascipt to blogger, follow these steps to add third party widgets to blogger
  1. go to dashboard of your blogger
  2. select your blog
  3. go to layout option
  4. when you see your layout, choose the add gadget option
  5. after this a pop-up will appear 
  6. choose html/ javascript option in that 
  7. paste your code there and check it saving it and viewing your blog