Javascript regex question

[xxarmoxx]

I am working on a special calculator and I want a regular expression to remove non-alpha characters and only allow 1 dot.

Here is the function I have so far:

function stripAlphaChars(pstrSource) { 

	var m_strOut = new String(pstrSource); 
	m_strOut = m_strOut.replace(/[^0-9\.]/g, '');

	return m_strOut; 
}

This code works fine for allowing 0-9 to be typed, but it removes dots.

Can someone help out?

I need to allow 0-9 and 1 single "."

Thanks