Discussion on: How to log user activities using the Beacon Web API?

Hi Tobias,

This is a great question. Yes, there is a limit and it is up to the user-agents(browser vendors) to decide what would be the limit.

The spec says,

The user agent must restrict the maximum data size to ensure that beacon requests are able to complete quickly and in a timely manner.

Check out this link for more details: w3.org/TR/beacon/#sec-sendBeacon-m...

For example, with research, I had found that someone tested the limit on an older version of chrome on windows and found the limit to be, (2^16).

Please take a look.

var url = 'http://jsfiddle.net?sendbeacon';
var n = 65536; // sendBeacon limit for Chrome v40 on Windows (2^16)

// this method courtesy of http://stackoverflow.com/questions/14343844/create-a-string-of-variable-length-filled-with-a-repeated-character
var data = new Array(n+1).join('X'); // generate string of length n

if(!navigator.sendBeacon(url, data))
{
   alert('data limit reached');
}