I want my background to cover the total width of the browser like in facebook website

<http://www.flickr.com/photos/41695354@N08/4228675694/>

but my background gives gaps on both side of the browser (left and right)

<http://www.flickr.com/photos/41695354@N08/4227911233/>

why this happens??

Help me

**my css**

```
body
{
color:#000000;
background-color:#FFFFFF;
}

.wrapper
{
 margin:0px auto;
 border:#000000 1px solid;
 height:38px;
 background-image:url(../images/logo_bck.jpg);
}

```

**html**

```
<body>
    <div class="wrapper">
        </div>
</body>

```