How to make a variable accessible across all pages in HTML / Template (Django)..?
Well, presumably you are dealing with form posts whenever you want to access the option you refer to.
You could either have your whole page be contained by a form, or use javascript to set a hidden field within your main form which is submitted. 
You can then access it as a raw property of the POST object, or bind a Form object to handle it.
I am using Django-Python for my project..I have created a "Master HTML page" and all other pages extends this master page..
There is a Drop down (Select Menu) in Master page..and i want to access the value of selected option across all Django Function and views..
How can i achieve that..??