When I render a page using the Django template renderer, I can pass in a dictionary variable containing various values to manipulate them in the page using {{ myVar }}
{{ myVar }}
The {{variable}} is substituted directly into the HTML. Do a view source; it isn't a "variable" or anything like it. It's just rendered text.
{{variable}}
Having said that, you can put this kind of substitution into your JavaScript.
This gives you "dynamic" javascript.