title: How do I find the top left of my SVG with d3?
body: <p>Given an SVG created with d3, for example using</p>
  
  <pre><code>svg = d3.select("#someElement").append("svg")...
  </code></pre>
  
  <p>how do I find the top and left of the SVG in the absolute coordinates of the <code>body</code>, so that I can, for example, absolutely position a tooltip or other element relative to the top -left of the SVG with something like</p>
  
  <pre><code>tooltip.style("left", leftInBody + 72 + "px").style("top", topInBody + 20 + "px"); 
  </code></pre>