var circles=svg.selectAll("circle").data(data).enter().append("circle").attr("id",function(d,i){return "circle"+i;}).attr("r",8).attr("fill","red").on("mouseover",function(d,i){ lines.style("stroke","#000"); }) .on("mouseout",function(d,i){ lines.style("stroke","#fff"); }) .call(force.drag);這個只是經過某一節點，把所有連線都顯示的代碼片段。