title: Live drawing of a line in D3.js
body: <p>I'm just started with D3.js, and I want to create something like what we do in Paint to draw a line. The steps are should be the same:
  - Click on a point on the screen
  - Drag to the destination to create a line.</p>
  
  <p>What I'm having troubles now is when you drag your mouse to the destination, the line should move according to your mouse. How can I do that?</p>
  
  <p>Thanks.</p>