chrome.devtools.network.getHAR does not work -

i trying create simple chrome extension number of http requests visible in network tab of chrome developer toolbar. added manifest.json:

{   "name": "entries",   "version": "1.0",   "description": "give me entries",   "devtools_page": "devtools.html",   "manifest_version": 2 }

devtools.html :

<html>     <body>         <script src="devtools.js"></script>     </body> </html>

devtools.js:

chrome.devtools.network.gethar(function(result) {     var entries = result.entries;        console.warn("entries : " + entries.length);  });

but when add extension --> open developer toolbar --> load page don't see result :( simple example.. can please me point if missing inputs here ?

is there way can debug ?

first of all, console doesn't exist, try console.

however, bigger issue here may writing wrong console. should became bit more understandable when you'll end of answer.

to debug custom devtools extensions have debug devtools devtools. if sounds madness follow these simple steps:

open devtools a website
detach devtools window (using button in lower left corner)
open devtools b (while in first devtools) using 1 of available keyboard shortcuts
enjoy debugging devtools a devtools b

everything output console extension in devtools a appear in console of devtools b.

Detect