function window_open(pagina,titulo,ancho,largo,x,y){

var Ventana= 'toolbar=0,location=0,directories=0,scrollbars=1,screenX='+x+',screenY='+y+',status=0,menubar=0,resizable=0,width='+ancho+',height='+largo;
open(pagina,titulo,Ventana);

}

function SubmitSellForm(){

document.sell.submit();
}
function ResetSellForm(){
document.sell.reset();
}
function SubmitPrevForm(){
document.preview.submit();
}
function ResetPrevForm(){
document.preview.reset();
}