Frequently asked questions

Syntax, keywords and built-in functions

Standard distribution

import implementation

Browser interface

Brython-specific built-in modules

Working with Brython



module browser.ajax

This module allows running Ajax requests. It defines a single class :

returns an ajax object

This object has the following attributes and methods :

attaches the function to the event evt. evt is a string that matches the different request states :

  • "uninitialized" : not initialized
  • "loading" : established connection
  • "loaded": received request
  • "interactive": response in progress
  • "complete" : finished

The function takes a single argument, the ajax object.

open(method, url, async)
method is the HTTP method used for the request (usually GET or POST),

url is the url to call,

async is a boolean that indicates whether the call is asynchronous (the script that started the request goes on running without waiting for the response) or not (the script hangs until the response is received).

an integer representing the request state (cf table below).

readyState request state

set_header(name, value)
sets the value of the header name.

set_timeout(duration, function)
if the query did not return response within duration in seconds, it will cancel the query and execute the function. This function cannot have arguments.

sends (starts) the request. The optional argument data is ignored if the method is not POST ; it must be a dictionary, or a string representing the url encoding of key-value pairs. If you want to send files, you need to pass a dictionary with one of the keys a File object, e.g. provided you have an input element of type file and id upload_file you could send the user selected file under the key upload by calling send({'upload':doc["upload_file"].elt.files[0]})

an integer representing the HTTP status of the request. The most usual are 200 (ok) and 404 (file not found).

the server response as a string of characters.

the server response as a DOM object.


We suppose there is a DIV with id result in the HTML page

from browser import document, ajax

def on_complete(req):
   if req.status==200 or req.status==0:
       document["result"].html = req.text
       document["result"].html = "error "+req.text

req = ajax.ajax()
# send a POST request to the url'POST',url,True)
# send data as a dictionary
req.send({'x':0, 'y':1})


GET and POST calls can be performed in a more straightforward way with the matching functions:

get(url[, async=True, headers={}, timeout=None, data="", **callbacks])

post(url[, async=True, headers={"Content-Type": "application/x-www-form-urlencoded"}, timeout=None, data="", **callbacks])

async is a boolean to specify if the request is asynchronous (default value) or synchronous (blocking)

headers is a dictionary with the HTTP headers key / values

data is either a string, or a dictionary. In the second case, the dictionary is converted into a string of the form x=1&y=2.

cache is a boolean to specify if the GET request should use the browser cache

timeout is the time in seconds after which the request is canceled

**callbacks is a dictionary where keys are of the form on + event name (onloaded, oncomplete...) and the value is the function that handles this event. For the key ontimeout, the value is the function to call if the duration defined in timeout has been reached.

The above example can be written with this shortcut:

from browser import document, ajax

def on_complete(req):
    if req.status == 200:
        document["result"].html = req.text
        document["result"].html = "error " + req.text,
          data={'x': 0, 'y': 1},