Javascript: How to sort an array of records by values in one of the fields?

A straightforward approach

var sorted = [{a:0,b:0},{a:2,b:1},{a:1,b:2}].sort( function( a, b )
{
  if ( a.a == b.a ) return 0;
  return ( a.a > b.a ) ? 1 : -1;
}).reverse();

EDIT

And a more flexible approach

// Note: console.log() require Firebug
var records = [{a:0,b:0},{a:2,b:1},{a:1,b:2}];
console.log( records );
// Sorty by 'a' ascending
sortByProperty( records, 'a' );
console.log( records );
// Sort by 'b' descending
sortByProperty( records, 'b', true );
console.log( records );
function sortByProperty( arr, property, descending )
{
  arr.sort( function( a, b )
  {
    return Boolean( descending )
      ? b[property] - a[property]
      : a[property] - b[property]
  } );
}

EDIT 2

A version that works for strings as well

// Note: console.log() require Firebug
var records = [
    {a:0,b:0}
  , {a:2,b:1}
  , {a:'banana',b:'apple'}
  , {a:1,b:2}
  , {a:'apple',b:'banana'}
];
console.log( records );
// Sorty by 'a' ascending
sortByProperty( records, 'a' );
console.log( records );
// Sort by 'b' descending
sortByProperty( records, 'b', true );
console.log( records );
function sortByProperty( arr, property, descending )
{
  arr.sort( function( a, b )
  {
    var c = a[property].toString()
      , d = b[property].toString()
    if ( c == d ) return 0;
    return Boolean( descending )
      ? d > c ? 1 : -1
      : d < c ? 1 : -1
  } );
}