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