openlayers wms spatial query

//Bind the mouse movement event to get the coordinate point

map.on('pointermove', function(evt) {

    if (evt.dragging) {
        return;
    }
    displayFeatureInfo(evt);

});

//Inquire

    var displayFeatureInfo = function (possibly) {

//Get the resource url generated by wms,  fdLayer.getSource().getGetFeatureInfoUrl

        var url = fdLayer.getSource().getGetFeatureInfoUrl(evt.coordinate, map.getView().getResolution(),
            'EPSG:4326', { 'INFO_FORMAT': 'application/json',

            'FEATURE_COUNT': 1 });

//http request result data

        $.ajax({
            url: url,
            async: false,
            dataType:'json',
            success: function (data) {

                    if (data.features.length > 0) {

// Parse the geojson result

                        var feature = data.features[0];

//Get the properties you want in the wms service

                        var fdid = feature.properties.fdid;
                        var fdno = feature.properties.fdno;       
                    } else {
                        content.innerHTML = '';
                        overlay.setPosition(undefined);
                    }
            }
        })

};