Actually Developer tools is not disabled, but Facebook discourages doing anything there, as many laypeople don’t know what it is.
They went on to display this message because of malicious users who instruct people to execute code in their browsers and who could potentially steal data from users.
I searched here, and the code that displays the message is relatively simple:
var i = "Stop!",
j = "This is a browser feature intended for developers. If someone told you to copy-paste something here to enable a Facebook feature or \"hack\" someone's account, it is a scam and will give them access to your Facebook account.";
if ((window.chrome || window.safari)) {
var l = 'font-family:helvetica; font-size:20px;';
[
[i, l + 'font-size:50px; font-weight:bold; ' + 'color:red; -webkit-text-stroke:1px black;'],
[j, l],
['', '']
].map(function(r) {
setTimeout(console.log.bind(console, '\n%c' + r[0], r[1]));
});
}
Basically, what the above code does is display a message on the console when it is detected that it has been opened.
Source: Console.log without Reference to the script
What options do you want to disable from Developer Tools? Because on Facebook I was able to use DT without problems.
– Daniel Gregatto
In FB the option Console this custom wanted to know if it is easy to modify it? I want to do the same in the Elements and Sources tabs if possible
– Rose
Related: http://answall.com/questions/6035/como_blockr-console-do-browser-usendo-javascript/
– user622