React img tag issue with url and class

Question

I have the following simple react code in my JSX file:

/** @jsx React.DOM */

var Hello = React.createClass({
    render: function() {
        return <div><img src='http://placehold.it/400x20&text=slide1' alt={event.title} class="img-responsive"/><span>Hello {this.props.name}</span></div>;
    }
});

React.renderComponent(<Hello name="World" />, document.body);

The output in the DOM is as follows:

<div data-reactid=".0">
  <img src="http://placehold.it/400x20undefined1" data-reactid=".0.0">
  <span data-reactid=".0.1">
    <span data-reactid=".0.1.0">Hello </span>
    <span data-reactid=".0.1.1">World</span>
  </span>
</div>

I have two issues with it:

• The image URL is rendered incorrectly, it is rendered as 'http://placehold.it/400x20undefined1'
• The class on my image disappears

Any ideas?

Answer 1

Remember that your img is not really a DOM element but a javascript expression.

1. This is a JSX attribute expression. Put curly braces around the src string expression and it will work. See http://facebook.github.io/react/docs/jsx-in-depth.html#attribute-expressions

2. In javascript, the class attribute is reference using className. See the note in this section: http://facebook.github.io/react/docs/jsx-in-depth.html#react-composite-components

   /** @jsx React.DOM */
   
   var Hello = React.createClass({
       render: function() {
           return <div><img src={'http://placehold.it/400x20&text=slide1'} alt="boohoo" className="img-responsive"/><span>Hello {this.props.name}</span></div>;
       }
   });
   
   React.renderComponent(<Hello name="World" />, document.body);