Make navigation bar take up entire page height in css

Question

I am designing a website using css and html. I have managed to get a navigation bar on the left side of my page using this css, however when the screen is scrolled down the navigation bar no longer continues.

#navbar {
  background: #a8a599;
  float: left;
  width: 20%;
  height: 100%;
}

However i would like to make the height of the navigation bar the height of the document. I feel like i might need java script for this, however i am new to java-script, so i am not sure how i would accomplish this. I thought making the height 100% would make it take up the whole page, owever it only takes up the visible part of the page.

Here it is on fiddle if you want to look at the rest of the page http://jsfiddle.net/HRpXV/3/embedded/result/

Answer 1

100% does not apply because it is floated. Change the parent container to position: relative and the navbar to position: absolute will solve the problem.

#container{
    position: relative;
}

#navbar {
    background: #a8a599;
    /*float: left; Instead of float, use absolute position*/
    position: absolute;
    width: 20%;
    height: 100%;
}

Demo