I have a div 

```
 <div id="chart" style="position:relative; width: 100%; float:left; height: 220px;">
</div>

```

And I need to change width dynamically. I found solution like:

```
var elem = document.getElementById('chart');

   elem.style.width = 70 + "%";

```

But that not work's. Where I do wrong ? Thanks in advance...