$.whenAll

gistfile1.js

var // Static reference to slice
  sliceDeferred = [].slice;

/* $.when that waits for everything to return before failing */
function whenAll( firstParam ) {
  var args = sliceDeferred.call( arguments, 0 ),
    i = 0,
    length = args.length,
    pValues = new Array( length ),
    count = length,
    pCount = length,
    deferred = length <= 1 && firstParam && jQuery.isFunction( firstParam.promise ) ?
      firstParam :
      jQuery.Deferred(),
    promise = deferred.promise(),
    fail = false;
  function resolveFunc( i ) {
    return function( value ) {
      args[ i ] = arguments.length > 1 ? sliceDeferred.call( arguments, 0 ) : value;
      if ( !( --count ) ) {
        fail? deferred.reject() :
              deferred.resolveWith( deferred, args );
      }
    };
  }
  function rejectFunc( i ) {
    var func = resolveFunc(i);
    return function (value) {
      fail = true;
      return func(value);
    }
  }
  function progressFunc( i ) {
    return function( value ) {
      pValues[ i ] = arguments.length > 1 ? sliceDeferred.call( arguments, 0 ) : value;
      deferred.notifyWith( promise, pValues );
    };
  }
  if ( length > 1 ) {
    for ( ; i < length; i++ ) {
      if ( args[ i ] && args[ i ].promise && jQuery.isFunction( args[ i ].promise ) ) {
        args[ i ].promise().then( resolveFunc(i), rejectFunc(i), progressFunc(i) );
      } else {
        --count;
      }
    }
    if ( !count ) {
      deferred.resolveWith( deferred, args );
    }
  } else if ( deferred !== firstParam ) {
    deferred.resolveWith( deferred, length ? [ firstParam ] : [] );
  }
  return promise;
}