How to change ReactJS styles dynamically?

I was trying to run ReactJS inside my twitter bootstrap web app. I have some issues using styles.

Having this div:

   ...
   <div class="ui-progressbar-value ui-widget-header ui-corner-left" style="width: 80%;"/>
   ...

I'm writing some dynamic progress bar, and would like to make that 80% change (look at ** underneath). So this is my code writing in JSX:

  var Task = React.createClass({
  render: function() {
  return (
  <li>
    <a href="#">
      <span className="header">
        <span className="title">{this.props.type}</span>
        <span className="percent">{this.props.children}%</span>
      </span>

      <div className="taskProgress progressSlim progressBlue" >
        <div className="ui-progressbar-value ui-widget-header ui-corner-left" 
       **style="width"+{this.props.value} +"%;" />**
      </div>
    </a>
   </li>
  );
 }
});

I read some documentation about the inline sytles, but the example is very light.

Thanks for your help.

Edit:

By using:

    style={{width : this.props.children}}

it works fine, but was just wondering how to force it as % instead of px.

Ok, finally found the solution.

Probably due to lack of experience with ReactJS and web development...

    var Task = React.createClass({
    render: function() {
      var percentage = this.props.children + '%';
      ....
        <div className="ui-progressbar-value ui-widget-header ui-corner-left" style={{width : percentage}}/>
      ...
     

I created the percentage variable outside in the render function.