Javascript regex question

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:

Code:

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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

Not sure if there's a more efficient way, but here's one thought...

Code:

---

function stripAlphaChars(pstrSource) {

  var m_strOut = new String(pstrSource);
  m_strOut = m_strOut.replace(/[^0-9\.]/g, '');
 
  var numOfDots = m_strOut.split(".").length-1;
  for(i=0;i<numOfDots-1;i++){
    m_strOut = m_strOut.replace(/\./, '');
  }

  return m_strOut;
}

---

The first replace takes out everything but numbers and dots. numOfDots gets the number of dots in the string. The for loop will do a non-global (replacing only the first instance that it finds) replace of dots until only one (the last) dot is left.

Code:

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foo.replace(/[^\d\.]/g, '').replace(/([\d]*)([\.]?)([\d]*)([\.\d]*)/g, '$1$2$3')

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Not too great...