Ryan

Easily add custom JavaScript or CSS to a single post or page.
When activated, a new icon is added to the post edit page near the icon you use 
to add media to a post. Clicking the new icon brings up a screen where you can 
insert JavaScript and CSS that will be included with the current post.
Anything entered into the text field on the JavaScript tab will be inserted into 
the <head> section of your web page. Same is true of the CSS tab. This allows 
you to insert arbitrary JavaScript and CSS into any post or page you would 
like without having to resort to loading it on all pages.

Insert JavaScript and CSS

Adds fields to the post and page edit pages that allow you to insert custom JavaScript or CSS for that post or page.

Jeremiah

Dealing with theme styles can be a hassle, but Style Buddy makes editing your WordPress site a breeze!
When the plugin is activated each page, post (and every other WordPress custom post type) gets metaboxes that allow you to add custom javascript and css to only that particular item. Let’s say you want to change the background color of your home page to black, but still want all your other pages to have a white background. With Style Buddy you just edit your homepage and add a command like body{background-color:black;} and only your home page background color will be changed.
Javascript is just as easy. Simply select the page or post you want, add your javascript to the specified metabox and you’re ready to go!
Want syntax highlighting for Style Buddy? Get it from <a href="https://wpovernight.com/downloads/style-buddy-pro/" rel="nofollow ugc">WP Overnight</a>.

Style Buddy

Add custom css and javascript to a page via the WordPress administration panel. Code is only loaded on the page to which it was added.

Insert JavaScript and CSS vs Style Buddy