d3.parcoords.js
function brushFor(axis) {
            var brush = d3.svg.multibrush();

            brush
                .y(__.dimensions[axis].yscale)
                .on("brushstart", function() {
                    if(d3.event.sourceEvent !== null) {
                        events.brushstart.call(pc, __.brushed);
                        d3.event.sourceEvent.stopPropagation();
                    }
                })
                .on("brush", function() {
                    brushUpdated(selected());
                })
                .on("brushend", function() {
                    // d3.svg.multibrush clears extents just before calling 'brushend'
                    // so we have to update here again.
                    // This fixes issue #103 for now, but should be changed in d3.svg.multibrush
                    // to avoid unnecessary computation.
                    brushUpdated(selected());
                    events.brushend.call(pc, __.brushed);
                })
                .extentAdaption(function(selection) {
                    selection
                        .style("visibility", null)
                        .attr("x", -15)
                        .attr("width", 30)
                        .style("fill", "rgba(255,255,255,0.25)")
                        .style("stroke", "rgba(0,0,0,0.6)");
                })
                .resizeAdaption(function(selection) {
                    selection
                        .selectAll("rect")
                        .attr("x", -15)
                        .attr("width", 30)
                        .style("visibility", null)
                        .style("fill", "rgba(0,0,0,0.1)");
                });

            brushes[axis] = brush;
            return brush;
        }
function brushFor(axis) {
            var brush = d3.svg.multibrush();

            brush
                .y(__.dimensions[axis].yscale)
                .on("brushstart", function() {
                    if(d3.event.sourceEvent !== null) {
                        events.brushstart.call(pc, __.brushed);
                        d3.event.sourceEvent.stopPropagation();
                    }
                })
                .on("brush", function() {
                    brushUpdated(selected());
                })
                .on("brushend", function() {
                    // d3.svg.multibrush clears extents just before calling 'brushend'
                    // so we have to update here again.
                    // This fixes issue #103 for now, but should be changed in d3.svg.multibrush
                    // to avoid unnecessary computation.
                    brushUpdated(selected());
                    events.brushend.call(pc, __.brushed);
                })
                .extentAdaption(function(selection) {
                    selection
                        .style("visibility", null)
                        .attr("x", -15)
                        .attr("width", 30)
                        .style("fill", "rgba(255,255,255,0.25)")
                        .style("stroke", "rgba(0,0,0,0.6)");
                })
                .resizeAdaption(function(selection) {
                    selection
                        .selectAll("rect")
                        .attr("x", -15)
                        .attr("width", 30)
                        .style("visibility", null)
                        .style("fill", "rgba(0,0,0,0.1)");
                });

            brushes[axis] = brush;
            return brush;
        }
function brushExtents() { var extents = {}; d3.keys(__.dimensions).forEach(function(d) { var brush = brushes[d]; if (brush !== undefined && !brush.empty()) { var extent = brush.extent(); extents[d] = extent; } }); return extents; }