title: jsPlumb anchors positions
body: <p>I am trying to customize jsPlumb to draw graphs, with all arrows going downwards, with connection-sources from the bottom-side of a container and connection-targets to the top-side of a container somewhere down the page.
  I use:</p>
  
  <pre><code>instance.connect({ source:"sourceDiv", target:"targetDiv" , anchors:["Bottom", "Top"] });
  </code></pre>
  
  <p>which works fine except one little issue...</p>
  
  <p>All arrows will originate from the <strong>middle</strong> of a bottom-side and terminate at the <strong>middle</strong> of a top-side.</p>
  
  <p>When there are many arrows going to/from the same container, I would rather like the anchors <strong>evenly spread out</strong> along the top-sides and bottom-sides.</p>
  
  <p>From the docs, I tried things like:</p>
  
  <pre><code>instance.makeSource("sourceDiv", { anchor: "Continuous" });
  instance.makeTarget("targetDiv", { anchor: "Continuous" });
  </code></pre>
  
  <p>or (with jQuery):</p>
  
  <pre><code>instance.makeSource($("#sourceDiv"), { anchor: "Continuous" });
  instance.makeTarget($("#targetDiv"), { anchor: "Continuous" });
  </code></pre>
  
  <p>But apparently not the right syntax... get errors like:</p>
  
  <pre><code>jsPlumb: fire failed for event connection : TypeError: info.connection.getOverlay(...) is null
  </code></pre>
  
  <p>Need help to sort this out.</p>