Convert between 4326 and 2272 with Proj4js. Written by @davewalk. Uses http://trac.osgeo.org/proj4js/

gistfile1.js

convertCoordinates: function (coords) {
  Proj4js.defs['EPSG:2272'] = '+proj=lcc +lat_1=40.96666666666667 +lat_2=39.93333333333333 +lat_0=39.33333333333334 +lon_0=-77.75 +x_0=600000 +y_0=0 +ellps=GRS80 +datum=NAD83 +to_meter=0.3048006096012192 +no_defs';

  var source = new Proj4js.Proj('EPSG:4326');
  var dest = new Proj4js.Proj('EPSG:2272');
  var point = new Proj4js.Point(-75.163789, 39.952335);
  Proj4js.transform(source, dest, point);
  return point;
}