React.createElement

React does provide some built-in shortcuts for creating commonly used HTML element nodes.
These shortcuts are called element factories.
An element-factory is a function that generates a ReactElement with a particular type property.

ReactDOM.render( 
   React.createElement("div", { className: "test" }, 
      React.createElement("h1", null, "My Heading") 
      React.createElement("p", null, "Some Text"} 
   ), 
   document.getElementById("myapp") 
) 

is equivalent to this javascript code

ReactDOM.render( 
   React.DOM.div( 
      {id : 'test' },  
      React.DOM.h1(null, 'My Heading'), 
      React.DOM.p(null, 'Some Text') 
   ), 
   document.getElementById("myapp") 
)