// Pop Up Window centred
function winPopCentre(theURL, theWin, theWidth, theHeight, theFeatures) {
    theTop=(screen.height/2)-(theHeight/2);
    theLeft=(screen.width/2)-(theWidth/2);
    winFeatures='height='+theHeight+',width='+theWidth+',top='+theTop+',left='+theLeft;
    if (theFeatures != undefined && theFeatures != "") {
        winFeatures = winFeatures + ',' + theFeatures;
    }
    winPopC = window.open(theURL,theWin,winFeatures);
}