The short answer is no, they are not. Although there are similarities between the two languages, they are separate languages (much like saying that apples and oranges are the same because they are both fruit).
Where Can I Get the Latest Browsers and Scripting Engines?
What Does All That Mean?
Where Can I Find Out More About ECMA-262?
You can download the specification from here: http://www.ecma.ch/ecma1/STAND/ECMA-262.HTM