This is a JavaScript function I often refer to for calculating BSA via various equations (rescued from the soon-to-be-shut-down parameterz googlecode repo).

``````
function calcBSA(wt, ht, BSAMethod) {
/// <summary>returns the body surface area in meters^2; calling with a single arg is assumed to be 'wt'</summary>
/// <param name="ht">height, units = cm</param>    /// <param name="wt">weight, units = kg</param>
/// <param name="BSAMethod">optional; type = string (any of the following:"DuBois", "Haycock"(default), "Gehan", "Mosteller", "Boyd", or "Dreyer")</param>
/// <returns>Number</returns>
// allow for ht and method to be optional:
if (!ht && !BSAMethod) {
// only one arg was passed, 'wt'
var BSAMethod = "Dreyer";
}
else if (!BSAMethod) {
var BSAMethod = "Haycock";
}
switch (BSAMethod) {
case "DuBois":
return 0.007184 * Math.pow(ht, 0.725) * Math.pow(wt, 0.425);
case "Haycock":
return 0.024265 * Math.pow(ht, 0.3964) * Math.pow(wt, 0.5378);
case "Gehan":
return 0.0235 * Math.pow(ht, 0.42246) * Math.pow(wt, 0.51456);
case "Mosteller":
return Math.sqrt((ht * wt) / 3600);
case "Boyd":
wt = wt * 1000;
var exponent = 0.7285 - 0.0188 * (Math.LOG10E * Math.log(wt)); //necessary to get the Log base 10 of (wt)
return 0.0003207 * Math.pow(ht, 0.3) * Math.pow(wt, exponent);
case "Dreyer":
return 0.1 * Math.pow(wt, (2 / 3));
default:
return 0.024265 * Math.pow(ht, 0.3964) * Math.pow(wt, 0.5378);// returns Haycock in the event an unfamiliar method is passed in
} //end switch
}
``````