title: Alternatives to replace ExtJS 1.2
body: <p>Im thinking in replace ExtJS 1.2 in a project that does not work in IE9 (only works in compatibility view and is so slowly  loading a tree). What JS frameworks are better (and trying to replacing as little posible the code?</p>
  
  <p>I see ExtJS 4 but has changed a lot compared with ExtJS 1.2</p>