title: Custom Mouseover Trigger d3.js javascript
body: <p>I am working with d3.js, and would like to create a custom event with a custom trigger.</p>
  
  <p>As I understand 'mouseover' event will be triggered when the mouse pointer is hovering above a certain element, i.e., horizontally and vertically the pointer is within the element.</p>
  
  <p>What I would like to do is to trigger a custom event, say 'xmouseover', that will be triggered as long as the mouse pointer is horizontally within the element. Shouldn't this be a simpler thing to do as I do not need to care about the vertical position?</p>