I have a html page with select combo box.

```
<select id="mySelect" name="Geometrical Figures">
  <option>Circle</option>
  <option>Triangle</option>
  <option>Square</option>
  <option>Rectangle</option>
  <option>Polygon</option>
</select>
<button  id="imagedraw" onclick="draw()">Draw Image</button>

```

I have different functions to draw canvas images based on user selection

```
function drawcircle()
function drawrectangle()
function drawtriangle()

```

My query is how can I set which function to call dynamically based on user input when `onclick` event is executed.  

Ex: When user selects circle and clicks on Draw Image, `drawCircle()` function would be called, similarly for other values.