JS 判断一个对象是否被分配一个值

/****************************************************************************
* Determines whether an object has been assigned a value.
*
* Returns TRUE if it has been assigned a value; FALSE otherwise
****************************************************************************/

 

function defined(obj)
{
  var str = typeof obj;

  if((str == "undefined") || (obj == null))
    return false;
  else
    return true;
}// END defined