Question: How do I change `width` value assigned in `#center`? (I don't want to switch between CSS files just because 1 changed `width` value.) How do I dynamically change the value using Javascript?

```html
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<style type="text/css">
    #main #center {
        width: 600px; // change width to 700 on click
        float: left;
    }

    #main #center .send {
        background: #fff;
        padding: 10px;
        position: relative;
    }

    #main #center .send .music {
        text-align: center;
        margin-bottom: 10px;
    }

    #main #center .send .write {
        font-family: georgia, serif;
        font-size: 150px;
        opacity: 0.2;
    }

    //....etc.
</style>
</head>

<body>
    // change #center width to 700
    <a href="#go2" onclick="how to change width of #center ???" ></a> 
</body>
</html>

```

Answer: 
```
document.getElementById('center').style.width = "599px";

```
```
<div onclick="changeWidth()" id="main">
Stuff
</div>

<div onclick="changeWidth()" id="center">
More Stuff
</div>

function changeWidth(){
   this.style.width = "700px";
}

```