text: var   w = 1000,
        h =  800,
        circleWidth = 5; 
   
  
  var palette = {
        "lightgray": "#E5E8E8",
        "gray": "#708284",
        "mediumgray": "#536870",
        "blue": "#3B757F"
    }
  
  var colors = d3.scale.category20();
  
  var nodes = [
        { name: "SJSU"},
        { name: "Engineering", target: [0], value: 58 },
        { name: "University Library", target: [0, 1], value: 65 },  
        { name: "Nutrition", target: [0, 1, 2], value: 52 },
        { name: "Public Chat", target: [0, 3], value: 48 }, 
        { name: "Events", target: [0,3,4,5], value: 36 },
        { name: "Nursing", target: [0,3,4,5], value: 42 }
        //{ name: "Social Work", target: [0, 1, 2], value: 52 },
        //{ name: "Food Science", target: [0, 1, 2, 8], value: 37 },
        //{ name: "Undergraduate", target: [0,1,2], value: 50 },
        //{ name: "Nutrition", target: [0,1,2,3,9], value: 67 },
        //{ name: "Nursing", target: [0,1,2,3,4,5,6,7,8,10], value: 68 },
        //{ name: "Geology", target: [0,1,2,7,8 ], value: 16 },
        //{ name: "Film", target: [0,1,2,7,8], value: 25 },
        //{ name: "Literature", target: [0,1,2,3,4,5,6,7,8,9,10,11,12], value: 45 },
        //{ name: "Journalism", target: [0,1,2,7,8], value: 25 }
  ];
  
  var links = [];
  
  for (var i = 0; i < nodes.length; i++){
        if (nodes[i].target !== undefined) { 
              for ( var x = 0; x < nodes[i].target.length; x++ ) 
                links.push({
                    source: nodes[i],
                    target: nodes[nodes[i].target[x]]  
                });
        };
  };
  
  
  var myChart = d3.select('body')
        .append("div")
          .classed("svg-container", true)
        
        .append('svg')
          .attr("preserveAspectRatio", "xMinYMin meet")
          .attr("viewBox", "0 0 1000 800")
          .classed("svg-content-responsive", true)
  
  
  var force = d3.layout.force()
        .nodes(nodes)
        .links([])
        .gravity(0.1)
        .charge(-1000)
        .size([w,h]); 
  
        var link = myChart.selectAll('line') 
              .data(links).enter().append('line')
              .attr('stroke', palette.lightgray)
              .attr('strokewidth', '1');
  
        var node =  myChart.selectAll('circle')  
              .data(nodes).enter() 
              .append('g') 
              .call(force.drag); 
  
       
       node.append('circle')
              .attr('cx', function(d){return d.x; })
              .attr('cy', function(d){return d.y; })
              .attr('r', function(d,i){
                    console.log(d.value);
                    if ( i > 0 ) {
                          return circleWidth + d.value; 
                    } else {
                          return circleWidth + 35; 
                    }
              })
              .attr('fill', function(d,i){
                    if ( i > 0 ) {
                          return colors(i);
                    } else {
                          return '#fff';
                    }
              })
              .attr('strokewidth', function(d,i){
                    if ( i > 0 ) {
                          return '0';
                    } else {
                          return '2';
                    }
              })
              .attr('stroke', function(d,i){
                    if ( i > 0 ) {
                          return '';
                    } else {
                          return 'black';
                    }
              });
  
  
        force.on('tick', function(e){ 
              node.attr('transform', function(d, i){
                return 'translate(' + d.x + ','+ d.y + ')'
              })
  
            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.append('text')
              .text(function(d){ return d.name; })
              .attr('font-family', 'Raleway', 'Helvetica Neue, Helvetica')
              .attr('fill', function(d, i){
                console.log(d.value);
                    if ( i > 0 && d.value < 10 ) {
                          return palette.mediumgray;
                    } else if ( i > 0 && d.value >10 ) {
                          return palette.lightgray;
                    } else {
                          return palette.blue;
                    }
              })
              .attr('text-anchor', function(d, i) {
                    return 'middle';
              })
              .attr('font-size', function(d, i){
                    if (i > 0) {
                          return '.8em';
                    } else {
                          return '.9em';    
                    }
              }) 
  
        node.on('click' , function(d)
          {
            if(d.name == "Engineering")
            {
              window.location.replace("services.html");
            }
            if(d.name == "Nutrition")
            {
              window.location.replace("nutrition.html");
            }
            if(d.name == "University Library")
            {
              window.location.replace("library.html");
            }
            if(d.name == "Public Chat")
            {
              window.location.replace("chat.html");
            }
            if(d.name == "Events")
            {
              window.location.replace("events.html");
            }
          
            
          });
  
  force.start();