why is the javascript and css unaltered on the web browser?

I just ran into a problem, While I was updating the js and css files for my website on a server, I do not see the immediate change. However, if I were to edit these files on a local computer or go on incognito mode on chrome, I see the change right away. let's say I have:

div{width:100px}

after I change it to div{width:200px}, when I pop open the developer tool, it still reads div{width:100px}.

I feel like I need to clear something for the broswer, any explanation for this?