can't access twitch DOM

Question

I just tried to move twitch.tv chat to the left side because it would be more comfortable to read chat on the left side.

I used this script in tampermonkey:

document.addEventListener("DOMContentLoaded", function(event) {
    var rightcol = document.getElementById('right_col');
    rightcol.style.right = "";
    rightcol.style.left = 0;
});

I set the script to run at the document-end and it runs, but the console says, I can't access 'style' of null. I checked the page source then and couldn't find the div with id 'right_col' either.
The site seems to be built with js scripts...

How do I access that div with id 'right_col' and change its style?

Solution:
Thanks to emmaaaah, I now use the chrome stylebot extension and this css to move the twitch chat to the left:

#right_col {
    right: initial ;
    left: 0 ;
}

#main_col, #left_col {
    left: initial ;
    right: 0 ;
    margin-left: 340px;
}

update 2:
I'm finally done with my changes. The chat is now on the left side, the menu is on the right side and all content has the right margins now.
I've made that my stuff available on github, if someone else also wants his twitch stream on the left side:
https://github.com/wullxz/twitchCssAdaptions

Answer 1

Try using Chrome StyleBot extension and creating a style in it, eg

.right_col {
  right: initial !important;
  left: 0 !important;
}