xxxxxxxxxx<meta charset="utf-8"><style>.node { stroke: #fff; stroke-width: 1.5px;}.link { stroke: #999; stroke-opacity: .6;}</style><body><script src="//d3js.org/d3.v3.min.js"></script><h2>Zachary's Karate Problem.</h2>Please select to see before or after split<select id="options"><option value="option1" selected="selected">No Split</option><option value="option2">Split</option><input type="submit" onclick="myFunction()"></select ><script> var width = 960, height = 500;var color = d3.scale.category20();var force = d3.layout.force() .charge(-120) .linkDistance(30) .size([width, height]);var svg = d3.select("body").append("svg") .attr("width", width) .attr("height", height);d3.json("output1.json", function(error, graph) { if (error) throw error; force .nodes(graph.nodes) .links(graph.links) .start(); var link = svg.selectAll(".link") .data(graph.links) .enter().append("line") .attr("class", "link") //.style("stroke-width", function(d) { return Math.sqrt(d.value); }); var node = svg.selectAll(".node") .data(graph.nodes) .enter().append("circle") .attr("class", "node") .attr("r", 8) //.on("click", function(d){ //.style("fill", function(d) { return color(d.faction); }) //}); .call(force.drag); node.append("title") .text(function(d) { return d.name; }); force.on("tick", function() { link.attr("x1", function(d) { return d.source.x; }) .attr("y1", function(d) { return d.source.y; }) .attr("x2", function(d) { return d.target.x; }) .attr("y2", function(d) { return d.target.y; }); node.attr("cx", function(d) { return d.x; }) .attr("cy", function(d) { return d.y; }); }); });function myFunction() { var drop1 = document.getElementById("options"); var selectedValue = drop1.options[drop1.selectedIndex].value; if (selectedValue == "option1"){ d3.selectAll(".node").style("fill", function(d) { return color(); }) } else{ //d3.selectAll(".node").style("fill", function(d) { return color(d.faction); }) d3.selectAll(".node").style("fill", function(d) { return color(d.faction); }) } }</script></body> https://d3js.org/d3.v3.min.js