<script>
proj4.defs('EPSG=26986', 'PROJCS["NAD83 / Massachusetts Mainland",GEOGCS["NAD83",DATUM["North_American_Datum_1983",' +
SPHEROID["GRS 1980",6378137,298.257222101]],PRIMEM["Greenwich",0],' +
'UNIT["degree",0.0174532925199433],PROJECTION["Lambert_Conformal_Conic_2SP"],' +
'PARAMETER["false_easting",200000],' +
'PARAMETER["false_northing",750000],' +
'PARAMETER[""central_meridian",-71.5],' +
'PARAMETER["latitude_of_origin",41],' +
'UNIT["metre"]]');

var map = new ol.Map({
layers: [
new ol.layer.Tile({
source: new ol.source.OSM()
})
],
target: 'map',
view: new ol.View({
projection: 'EPSG=26986',
center: ol.proj.fromLonLat([-71, 42], 'EPSG=26986'),
zoom: 7,
extent: ol.proj.transformExtent([-172.54, 23.81, -47.74, 86.46],
'EPSG:4326', 'EPSG=26986'),
minZoom: 6
})
});

map.addControl(new ol.control.ScaleLine({units: 'us'}));
</script>