Div height percentage based but still scrolling

Question

First off, similar but never answered questions:

vertically-scrolling-percentage-based-heights-vertical-margins-codepen-exampl

scroll-bar-on-div-with-overflowau

Answer 1

You could try the following.

You HTML is:

    
The header...
    

        

            
example
             ...
            
example
        
        

            

                
            
        
    

Apply the following CSS:

html, body {
    height: 100%;
}
body {
    margin:0;
}
#header {
    background:#333;
    height: 50px;
    position: fixed;
    top: 0;
    width: 100%;
}
#content {
    position: absolute;
    top: 50px;
    left: 0;
    right: 0;
    bottom: 45px;
    overflow-y: scroll;
}
#messages {
    overflow: auto;
}
#messages .message {
    height: 79px;
    background: #999;
    border-bottom: 1px solid #000;
}
#input {
    position:fixed;
    bottom:0;
    left:0;
    width:100%;
    height: 45px;
}
#input .spacer {
    padding: 5px;
}
#input input {
    width: 100%;
    height: 33px;
    font-size: 20px;
    line-height: 33px;
    border: 1px solid #333;
    text-indent: 5px;
    color: #222;
    margin: 0;
    padding: 0;
}

See demo at: http://jsfiddle.net/audetwebdesign/5Y8gq/

First, set the height of 100% to the html and body tags, which allows you to reference the view port height.

You want the #header to be fixed towards the top of the page using position: fixed, similarly for your footer #input.

The key is to use absolute positioning on #content to stretch it between the bottom edge of the header and the top edge of the footer, and then apply overflow-y: scroll to allow it to scroll the content (list of messages).

Comment
The source code for the #input block may be placed outside of the #content block.