JSX lets you put markup into JavaScript. Curly braces let you “escape back” into JavaScript so that you can embed some variable from your code and display it to the user. For example, this will display user.name:

 return ( 
 < h1 > 
 { user . name } 
 </ h1 > 
 ) ; 

You can also “escape into JavaScript” from JSX attributes, but you have to use curly braces instead of quotes. For example, className="avatar" passes the "avatar" string as the CSS class, but src={user.imageUrl} reads the JavaScript user.imageUrl variable value, and then passes that value as the src attribute:

 return ( 
 < img 
 className = "avatar" 
 src = { user . imageUrl } 
 /> 
 ) ;