function openWindow(size, width, height){
    var browser = navigator.appName;
    width = 1024;
    height = 768;
    swidth = ((screen.width/2)-(width/2));
    sheight = ((screen.height/2)-(height/2));
    macwidth = width-16;
    macheight = height-16;
      
    if ((browser == "Microsoft Internet Explorer") && (navigator.appVersion.lastIndexOf('Mac') != -1)){ 
    	window.open('main/index.html','elearning','width='+ macwidth +',height='+ macheight +',top='+ sheight +',left='+ swidth +',resizeable=no');
	}
    else
    {
    	window.open('main/index.html','elearning','width='+ width +',height='+ height +',screenY='+ sheight +',screenX='+ swidth +',top=' + sheight + ',left=' + swidth + ',resizeable=no');
    }
}