Question: I'm working on a codebase with multiple blocks of code setting some behavior on document.ready() (jQuery). Is there a way to enforce that one specific block is called before any of the others? 

Background:
I need to detect JS errors in an automated testing environment, so I need the code that starts logging JS errors to execute before any other JS code executes.

Answer: 
As @jfriend00 mention that `ready callbacks are called in the order they were registered.`

So even if this code block called on the beginning, you can set another callback in it so it'll be executed on endmost.

```js
jQuery(document).ready(function(){
    jQuery(document).ready(function(){
        // This block will be executed after all ready calls.
    });
});

```
You should be able to use [holdReady](http://api.jquery.com/jQuery.holdReady/) to do this. As long as it is included before your ready events, you can run your own code and then trigger the other ready events.