javascript - Enable scroll for a div but lock it for another one -

this website http://www.yarrutfranken.com/

if press 'plus' button on homepage contact information show up. can not scroll on black page. (try making window smaller see).

there's text falling off when on 11" or 13" laptop.

so wrap up:

• need scroll on black information page
• if information page active scroll must blocked on 'homepage'.

please me.

ps: i'm not hero in javascript or other stuff. just;

• html
• css
• jquery

add overflow-y: auto; #actinfo css rule in order allow scroll if content higher element's height.

#actinfo {   width: 80%;   height: 100%;   background-color: black;   position: fixed;   z-index: 4000;   overflow-y: auto; }