JavaScript - Sum of the first X prime numbers

I recently had a programming challenge where I had to find the sum of the first X prime numbers in JavaScript in a slightly compressed format, and couldn't find anything decent online.

So I coded this.


It could be far better, although the challenge was timed :P

Thanks to The Polyglot Developer for their "isPrime" function :)

A Textbox that only allows numbers

Since this seems so hard to do... An actual working example :)

Usage HTML: <input type="text" onkeypress="return isNumericKeyPress(event.keyCode);" onpaste="isNumericPaste(this);" />

OR

ASP.NET: <asp:textbox ID="txtNumsOnly" runat="server" onkeypress="return isNumericKeyPress(event.keyCode);" onpaste="isNumericPaste(this);"></asp:textbox>

Demo Type or paste something:

Samples
- 1!2@3#
- Test
- Test1
- 1a2b3c