Full page body background image

Question

I have a webpage which has several collapsable divs, the thing is that when I open more than once, the height of the background image I have on my body gets broken, at the end of the page I get a black background and the background isn't covering the whole page.

How could I fix this?.

Regards

For my body on CSS I'm using this:

body {
    background-image: url(../img/fondo_pantalla_bandadelcarmen_mar.jpg) !important; 
    background-position:center center !important;
    background-repeat:no-repeat !important;
    -webkit-background-size: cover !important;
    -moz-background-size: cover !important;
    -o-background-size: cover !important;
    background-size: cover !important;
}

Answer 1

  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;

For further reference see This