Implementing JS script within forum? (Snow Effect)

[Inked_Mono]

Hey, everyone! I'm just wondering what the best way to implement as JS script I have would be. The JS itself is currently being hosted off the FTP titled "snow.js", and I've tried sticking the following in many different places (footer and header included);

< script src="./snow.js" >< /script >

For whatever reason, I can't seem to get it to load. Also, something to sort of keep in mind is I have the following assigned as a div:

<div id="particles-js"></div>

and the following CSS:

#particles-js {
            position: absolute;
            width: 100%;
            height: 780px;
            left: 0;
            top: 0;
            opacity: 0.9;
        }

The main page URL for the site is as follows, which currently contains the snow effect I'm trying to get on the forum;

https://www.os-scape.com/

Could anybody help?