How to use 100% CSS background-image with scrolling content?

Question

I want to create a site with a background image that always fills the entire window, even if the content can scroll vertically.

I have created this JSFiddle using ba

Answer 1

    #appcontainer {
        position: absolute;
        background-color: rgba(255, 255, 255, 0.7);
        background: url(images/bg.jpg) no-repeat center center fixed; 
        -webkit-background-size: cover;
        -moz-background-size: cover;
        -o-background-size: cover;
        background-size: cover;
        top: 0;
        right 0;
        left: 0;
        bottom 0;
    }