var visible;
var hidden;


if (document.layers) {
	visible = 'show';
	hidden = 'hide';
}

else if (document.all) {
	visible = 'visible';
	hidden = 'hidden';
}



function rollover(imageName) {
 	if (document.images && loaded) {
		document.images[imageName].src = "/img/" + imageName + "-on.gif";
	}
}

function rolloff(imageName) {
 	if (document.images && loaded) {
		document.images[imageName].src = "/img/" + imageName + "-off.gif";
	}
}

function popup(windowname) {
	var thiswin= open('',windowname,'width=600,height=600,scrollbars=yes');
	if (thiswin.focus) thiswin.focus();
}

function popupSized(windowname, width, height) {
	var thiswin= open('',windowname,'width=' + width + ',height=' + height + ',scrollbars=yes');
	if (thiswin.focus) thiswin.focus();
}

function askDelete(id) {
	if (confirm("Are you sure you want to delete this person?")){
		popup('popup');
	};
}


function printPage() {

        if(window.print) {
                window.print();
        } else {
                alert('Your browser does not support this feature. You should be \nable to print ' +
                        'using the menu which appears when you\n right click this page, however.\n\n' +
                        'Upgrade to either Netscape 4 or Internet Explorer 5 to make \nthe Print button ' +
                        'work (this software is usually available \non any computer magazine coverdisk, or '+
                        'can be downloaded \nfrom the Internet if you have a fast connection).');
        }
}

function colourchange(box) { 
	if (document.images) {
		document.images[box].src = "/img/" + box + "-l.gif"; 
		return true; 
		}
	}

function uncolourchange(box) {
	if (document.images) {
		document.images[box].src = "/img/" + box + "-g.gif";
		return true; 
		} 
	}



function Validate(objForm) { 
// checks all compulsory fields are filled 

var objForm = document.contact_form;

////////////////// 
// email 
////////////////// 
if (objForm.email.value == "") { 
	alert("You have not included your email address.\n"+ 
	"This information is required to process your submission.");
	return false;
	}

if(objForm.email.value != "") { 
// tried to enter an email address, so make sure it contains 
// no spaces, and has an @ and a . in it 

strEmail = objForm.email.value; 

if(strEmail.indexOf("@")== -1 || strEmail.indexOf(".")== -1 || strEmail.indexOf(" ")!= -1) { 

alert("Please make sure the email address you have specified is\n of " + 
	"a valid format, e.g. joe@bloggs.co.uk.");
	return false; 
	}
}

////////////////// 
// contact 
////////////////// 
if (objForm.contact.value == "") { 
	alert("You have not included your comments.\n"+ 
	"This information is required to process your submission."); 
	return false; 
	} 
} 
//!--> 



<!-- today = new Date();

function colourchange(box) { if (document.images) { document.images[box].src = "/img/" + box +
"-l.gif"; return true; } }

function uncolourchange(box) { if (document.images) { document.images[box].src = "/img/" + box +
"-g.gif"; return true; } } //-->