//pop up centre window code  J Wheeler  james@iveygreen.com

 if (document.all || document.getElementById)
        var xMax = screen.width, yMax = screen.height;
    else
        if (document.layers)
            var xMax = window.outerWidth, yMax = window.outerHeight;
        else
            var xMax = 1024, yMax=768;

function openCentre(URLtoOpen, windowName, windowWidth, windowHeight, scrollBars, resiZable) {
    var xOffset = (xMax - windowWidth)/2, yOffset = (yMax - windowHeight)/2;  

    window.open(URLtoOpen, windowName, 'width='+windowWidth+',height='+windowHeight+', status=no,toolbar=no,menubar=no,location=no,scrollbars='+scrollBars+',resizable='+resiZable+',screenX='+xOffset+',screenY='+yOffset+',top='+yOffset+',left='+xOffset+'');
}