Passing django variables to javascript via templates

I can fairly say, that reasonable web applications can't exist without a bit of javascript. We all remember those static web pages that were popular in the late 90'. Well their time is up, professional websites frontend is built using HTML/XHTML/HTML5 + CSS + JS (sometimes Flash).

AJAX requests or newer synchronous pull/push methods enable achieving some dynamic connectivity between frontends and backends. It is also possible to pass some initialization data this way, however if your website architecture is not a real-time client-server (ex. WebSockets) this may be inefficient.

A good practice is initializing JS variables along with rendering pages, so additional initialization request are not required. A simple way of implementing this mechanism is passing JSON encoded data to the template and decoding it in JavaScript. Lets implement the appropriate django view:

def init_js_template(request):
    import json
    json_data = json.dumps({'test' : '12345', 'arr' : [1,2,3]})
    return render_to_respons('init_json.html', {'json_data':json_data})

And the corresponding javascript initialization in the init_json.html template:

This way you will save some resources by reducing the number AJAX calls. Just keep in mind that this will only work for arrays/dictionaries containing primitive types or other arrays.

~KR