Script per adattare lunghezza colonne css

[Coralba]

Salve, sono neofita di Javascript e mi serviva una script per adattare la lunghezza delle colonne in un css e ne ho trovato uno per un template a due colonne.
Dovevo riadattarlo però per un box_model a TRE colonne.
Ho fatto le modifiche che mi sembravano appropriate ma lo script non funziona.
Qualcuno è in grado di dirmi dove sbaglio?
Posto qui sotto lo script:

addLoadListener(equalHeight);

function equalHeight() {

var myLeftColumn = document.getElementById("center_border_sx");
var myCenterColumn = document.getElementById("centro_center_border");
var myRightColumn = document.getElementById("center_border_dx");

var myLeftHeight = myLeftColumn.offsetHeight;
var myCenterColumn = myCenterColumn.offsetHeight;
var myRightHeight = myRightColumn.offsetHeight;

var myLeftBorderTopPixels = retrieveComputedStyle(myLeftColumn, "borderTopWidth");
var myLeftBorderBottomPixels = retrieveComputedStyle(myLeftColumn, "borderBottomWidth");
var myLeftPaddingTopPixels = retrieveComputedStyle(myLeftColumn, "paddingTop");
var myLeftPaddingBottomPixels = retrieveComputedStyle(myLeftColumn, "paddingBottom");

var myCenterBorderTopPixels = retrieveComputedStyle(myCenterColumn, "borderTopWidth");
var myCenterBorderPixels = retrieveComputedStyle(myCenterColumn, "borderBottomWidth");
var myCenterBorderTopPixels = retrieveComputedStyle(myCenterColumn, "paddingTop");
var myCenterBordergBottomPixels = retrieveComputedStyle(myCenterColumn, "paddingBottom");

var myRightBorderTopPixels = retrieveComputedStyle(myRightColumn, "borderTopWidth");
var myRightBorderBottomPixels = retrieveComputedStyle(myRightColumn, "borderBottomWidth");
var myRightPaddingTopPixels = retrieveComputedStyle(myRightColumn, "paddingTop");
var myRightPaddingBottomPixels = retrieveComputedStyle(myRightColumn, "paddingBottom");

var myLeftBorderNumber = Number(myLeftBorderTopPixels.replace("px", "")) + Number(myLeftBorderBottomPixels.replace("px", ""));
var myLeftPaddingNumber = Number(myLeftPaddingTopPixels.replace("px", "")) + Number(myLeftPaddingBottomPixels.replace("px", ""));
var myLeftExtras = myLeftBorderNumber + myLeftPaddingNumber;

var myCenterBorderNumber = Number(myCenterBorderTopPixels.replace("px", "")) + Number(myCenterBottomPixels.replace("px", ""));
var myCenterPaddingNumber = Number(myCenterPaddingTopPixels.replace("px", "")) + Number(myCenterPaddingBottomPixels.replace("px", ""));
var myCenterExtras = myCenterBorderNumber + myCenterPaddingNumber;

var myRightBorderNumber = Number(myRightBorderTopPixels.replace("px", "")) + Number(myRightBorderBottomPixels.replace("px", ""));
var myRightPaddingNumber = Number(myRightPaddingTopPixels.replace("px", "")) + Number(myRightPaddingBottomPixels.replace("px", ""));
var myRightExtras = myRightBorderNumber + myRightPaddingNumber;

if (myLeftHeight > myRightHeight) {
myRightColumn.style.height = (myLeftHeight - myRightExtras) + "px";
}

else {
myLeftColumn.style.height = (myRightHeight - myLeftExtras) + "px";
}


if (myCenterHeight > myRightHeight) {
myRightColumn.style.height = (myCenterHeight - myRightExtras) + "px";
}

else {
myCenterColumn.style.height = (myRightHeight - myCenterExtras) + "px";
}

if (myLeftHeight > myCenterHeight) {
myRightColumn.style.height = (myLeftHeight - myCenterExtras) + "px";
}

else {
myLeftColumn.style.height = (myCentertHeight - myLeftExtras) + "px";
}

}

function retrieveComputedStyle(element, styleProperty)
{
var computedStyle = null;

if (typeof element.currentStyle != "undefined")
{
computedStyle = element.currentStyle;
}
else
{
computedStyle = document.defaultView.getComputedStyle(element, null);
}
return computedStyle[styleProperty];
}

function addLoadListener(fn)
{
if (typeof window.addEventListener != 'undefined')
{
window.addEventListener('load', fn, false);
}
else if (typeof document.addEventListener != 'undefined')
{
document.addEventListener('load', fn, false);
}
else if (typeof window.attachEvent != 'undefined')
{
window.attachEvent('onload', fn);
}
else
{
var oldfn = window.onload;
if (typeof window.onload != 'function')
{
window.onload = fn;
}
else
{
window.onload = function()
{
oldfn();
fn();
};
}
}
}

[Coralba]

Esclusi errori di "ortografia"...nessuno che può aiutarmi?