Combine multiple text inputs and copy into another using javascript : I have several text boxes, all with the same class. 
What I am wanting to do is combine all inputs together, and then output it to another text field, separate to the existing ones

For example. I have 4 inputs, each with a number. 

Input 1 is "1"
2 is "2" etc, 
I want the fifth box to contain "1, 2, 3, 4" (the contents from the 4 boxes above).

I have the following code for the html:

    <input type='text' id='txtFirst' class='copyText' /><br/>
    <input type='text' id='txtSecond' class='copyText' /><br/>
    <input type='text' id='txtThird' class='copyText' /><br/>
    <input type='text' id='final' />

But I am struggling with the javascript.
Ideally the fourth box with id final would update as any of the previous boxes are edited.
Also, I would want to do it using the classes, as the amount of inputs can vary, so its not possible to assume it will always be four.
Many thanks!


