// Open a new centred window
// Opens different window if windowName unique
// doc = page address
// winWidth = window width
// winHeaight = height of window
// windowName = name of window


function newWin (doc, winWidth, winHeight,windowName){
    var width = (screen.width)/2 - winWidth/2;
    var height = (screen.height)/2 - winHeight/2;
    winProps = 'height='+winHeight+',innerHeight=380'+winHeight+',width='+winWidth+',innerWidth='+winWidth+',top='+height+',left='+width+',scrollbars=yes' 
    windowName = window.open(doc,windowName,winProps)
  }