drawChart = function(){
let svg = d3.select("#dots")
.append("svg")
.attr("width",width)
.attr("height",height);
var simulation = d3.forceSimulation(nodes)
.force('charge', d3.forceManyBody())
.force("x", d3.forceX())
.force("y", d3.forceY())
.force("center", d3.forceCenter());
let node = svg.append("g")
.selectAll("circle")
.data(nodes)
.join("circle")
.attr("cx", d => Math.random()*width)
.attr("cy", d => Math.random()*height)
.attr("r", 2)
.attr("fill", "blue")
.attr("fill-opacity", 1);
}