Capture/save user variables using 'onclick'

Hi there - can someone help me capture data when a user hits the button below? ie. can I have two actions on an 'onclick', or do I need to add something to the function?

Attached: function, onclick statement and URL Appreciate your help.

function pwave_calc(GeoForm)
{
var pwavelamda = GeoForm.lamda.value;
var pwavemu = GeoForm.mu.value;
var pwaverho = GeoForm.rho.value;

if (pwaverho > 0)
{
GeoForm.pwave.value = Math.sqrt ( (pwavelamda + 2 * pwavemu) / pwaverho ) ;
}
else
{
GeoForm.pwave.value = "";
}
}

ONCLICK Statement:

<input type=BUTTON onClick="pwave_calc(this.form);" value="calculate" name="BUTTON">

URL:
URL

Thanks

You want the javascript/html forum