Get previous object id which isn't disabled
<p>Dear Stackoverflowers,</p>

<p>I got the following object and function, but if i give 0 as parameters it bugs!
Please help me out since i have only 1,5 hour left to deliver this.</p>

<pre><code>var album =
[
    {
      url: 'images/0006787.jpg',
      landscape: true,
      description: 'Shadows to the sea...',
      photographer: 'Sander',
      date: '12-8-1999'
    },
    {
      url: 'images/0004713.jpg',
      description: 'Amsterdam? Utrecht? Die fiets ben je kwijt!',
      landscape: false
    },
    {
      url: 'images/0004720.jpg',
      landscape: false
    },
    {
      url: 'images/0004731.jpg',
      landscape: true
    },
    {
      url: 'images/0004750.jpg',
      landscape: true
    },
    {
      url: 'images/0004755.jpg',
      landscape: true
    },
    {
      url: 'images/0004801.jpg',
      landscape: true
    },
    {
      url: 'images/0004802.jpg',
      landscape: false
    },
    {
      url: 'images/0004827.jpg',
      landscape: false
    },
    {
      url: 'images/0004853.jpg',
      landscape: false
    },
    {
      url: 'images/0004858.jpg',
      landscape: true
    },
    {
      url: 'images/0004860.jpg',
      landscape: true
    },
    {
      url: 'images/0004870.jpg',
      landscape: true
    },
    {
      url: 'images/0004874.jpg',
      landscape: false
    },
    {
      url: 'images/0004888.jpg',
      landscape: true
    },
    {
      url: 'images/0004902.jpg',
      landscape: true
    },
    {
      url: 'images/0004931.jpg',
      landscape: true
    },
    {
      url: 'images/0004969.jpg',
      landscape: true
    },
    {
      url: 'images/0004971.jpg',
      landscape: true
    },
    {
      url: 'images/0006598.jpg',
      landscape: true
    },
    {
      url: 'images/0006630.jpg',
      landscape: true
    },
    {
      url: 'images/0006638.jpg',
      landscape: true
    },
    {
      url: 'images/0006680.jpg',
      landscape: true
    },
    {
      url: 'images/0006743.jpg',
      landscape: true
    },
    {
      url: 'images/0004681.jpg',
      landscape: false
    }
];
</code></pre>

<p>The function:</p>

<pre><code>function getPrev(currPhotoId) {
    var i = currPhotoId - 1;
    i %= album.length;
    while ( album[i].disabled ) {
        i--;
        i %= album.length;
    }
    return i;
}
</code></pre>

<p>Now the purpose of this function is that it checks if the previous row has the property disabled, if it does it scans until it finds one without the disabled property.</p>

<p>For example
getPrev(0) should return last in object in this case.
But, if i the last in object to disabled = true, it should scan backwards untill it reaches one without the disabled property</p>
