can't load arcgis service WFS Layer?

[songsgroup]

in example "chapter03_07_query_wfs.html", i changed wfs data to
var url = '/proxy.ashx?http://dtc-sci02.esri.com/arcgis/services/OGC_DevSummit2014/MarineEcoRegions/MapServer/WFSServer?' + 'service=WFS&request=GetFeature&' + 'version=1.1.0&typename=OGC_DevSummit2014_MarineEcoRegions:MEOW_ECO&' + 'srsname=EPSG:3857&' + 'bbox=' + extent.join(','); data show in firebug but not showing in map;