bla.js

var data = [1,3,5,10,11,12,50];

var width = 500,
  height = 100,
  r = 5;

var xScale = d3.scale.linear()
  .range([5, width-r])
  .domain([1,50]);

var chart = d3.select("#vis")
  .append("svg")
  .attr("width", width)
  .attr("height", height);

var circles = chart.append("g")
  .classed("circles", true);

circles.selectAll("circle")
  .data(data)
  .enter()
    .append("circle")
    .classed("circle", true)
    .style("fill", "red")
    .attr("r", r)
    .attr("cy", height/2)
    .attr("cx", function(d) {
      return xScale(d);
    });