// Preload images
var empty = new Image(); empty.src = "fieldempty.gif";
var email = new Image(); email.src = "emailerror.gif";
var phone = new Image(); phone.src = "phoneerror.gif";

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

function validateForm(f) {
haveerrors = 0;
(f.Name.value.length < 1) // validate first name length
? showImage("tf100error", "images/fieldempty.gif", true)   // no semi-colon after this line!
: showImage("tf100error", "images/blankimage.gif", false); // true = errors, false = no errors

(f.email.value.search("@") == -1 || f.tf800.value.search("[.*]") == -1) // validate email
? showImage("tf800error", "images/emailerror.gif", true)
: showImage("tf800error", "images/blankimage.gif", false);

(f.Comment.value.length < 1) // validate comments length
? showImage("ta100error", "images/commentempty.gif", true)
: showImage("ta100error", "images/blankimage.gif", false);

return (!haveerrors);
}