title: Issue in showing series of data in javascript
body: <p>My friends,</p>
  
  <p>i have made a tooltip here: <a href="http://jsfiddle.net/QBDGB/83/" rel="nofollow">http://jsfiddle.net/QBDGB/83/</a> and I have defined two "functions" for tooltip like: </p>
  
  <pre><code>function mousemove1(d) {
      div
        .text("data 1: " + d.value + " at " + formatTime(new Date(d.time)))
        .style("left", (d3.event.pageX) + "px")
        .style("top", (d3.event.pageY) + "px");
  }
  
  function mousemove2(d) {
      div
        .text("data2: " + d.value + " at " + formatTime(new Date(d.time)))
        .style("left", (d3.event.pageX) + "px")
        .style("top", (d3.event.pageY) + "px");
  }
  </code></pre>
  
  <p>but when i move the cursor it shows the value of "data2" where is data1? I want the tooltip recognize the two series of data and show their value when we hover around the two curves of graph.</p>