function coordx(w) {
  	var w2 = Math.ceil( w/2);
  	var windowX = Math.ceil( window.screen.width  / 2 )-w2;
  	return windowX; 
}
  
function coordy(h) {    
  	var h2 = Math.ceil( h/2);
  	var windowY = Math.ceil( window.screen.height / 2 )-h2;
  	return windowY;
}

function obrirFlotant(arg,arg2) {
    var aux=escape(arg2);
	window.open(arg+'.htm?'+aux, "flotant", "toolbar=0, width=590, height=320, top="+coordy(300)+",left="+coordx(600));
}