// JavaScript Document

var empty = new Image(); empty.src = "images/fieldempty.gif";

var haveerrors = 0;
function showImage(imagename, imageurl, errors) {
document[imagename].src = imageurl;

if (!haveerrors && errors) haveerrors = errors;
}
function validateForm(f) {
haveerrors = 0;


/*(f.isbnp.value.length != 10 && f.isbnc.value.length < 1 ||  f.isbnc.value.length != 10 && f.isbnp.value.length < 1 || f.isbnc.value.length != 10 && f.isbnp.value.length != 10) */
(f.isbnp.value.length != 10 && f.isbnp13.value.length < 1 && f.isbnc.value.length < 1 f.isbnc13.value.length < 1 ||
 f.isbnc.value.length != 10 && f.isbnc13.value.length < 1 && f.isbnp.value.length < 1 && f.isbnp13.value.length < 1 || 
 f.isbnp13.value.length != 13 && f.isbnp.value.length < 1 && f.isbnc.value.length < 1 f.isbnc13.value.length < 1 ||
 f.isbnc13.value.length != 13 && f.isbnc.value.length < 1 && f.isbnp.value.length < 1 && f.isbnp13.value.length < 1 || 
 f.isbnc.value.length != 10 || f.isbnp.value.length != 10 || f.isbnc13.value.length != 13 && f.isbnp13.value.length != 13 )
? showImage("isbnp_error", "../images/fieldempty.gif", true)
: showImage("isbnp_error", "../images/blankimage.gif", false);

return (!haveerrors);
}