title: D3 mousedown triggers on load
body: <p>mousedown and mouseup triggering on load and then not again. 
  I'm doing something wrong here. 
  Any tips appreciated.</p>
  
  <p>-------- mousecrazy.js ----------</p>
  
  <pre><code>yesClick = function() {
      alert("always");
  }
  
  var svgbox = d3.select('body')
      .append('svg')
      .attr('width', 500)
      .attr('height', 250)
      .on("mousedown", yesClick())
      .on("mouseup", yesClick());
  </code></pre>
  
  <p>-------- mousecrazy.html ----------</p>
  
  <pre><code>&lt;html&gt;
  &lt;head&gt;
      &lt;script src='http://d3js.org/d3.v3.min.js'&gt;&lt;/script&gt;
      &lt;script src="js/mousecrazy.js"&gt;&lt;/script&gt;
      &lt;title&gt;mousecrazy&lt;/title&gt;
  &lt;/head&gt;
  &lt;body&gt;
  
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>