rgbflawed rgbflawed - 1 year ago 144
Javascript Question

What is Facebook's function __d

I'm working on a project that (hopefully) involves taking advantage of some of the javascript that's already built into Facebook. But right away I've got a roadblock in that I can't figure out what


If you look at the source javascript files, pretty much every command begins with

For example:


But I can't find anywhere in any of the javascript files what
actually does. Shouldn't it have to be defined somewhere for all these other functions to take advantage of it?


So let's say there's a site with some javascript like this...

function alertSomething(var) {
if (var) alert("Here it is: "+var);

if (some condition) alertSomething("something");

Now let's say I had a Chrome Extension and I was able to inject my own Javascript into the page. Couldn't \my Chrome Extension Javascript have something like this...

if (some other condition) alertSomething("something else");

Thus I would be taking advantage of some code that exists in the javascript already on the page?

Answer Source

I found the definition of __d on line 20 of 1LWPxIBQ4v0.js. No idea if the file is named the same for everyone. Search for "a.__d=function(s,t,u,v)" (a is the global object, i.e. window, effectively making __d a global function). Good luck with that de-minification though...