function full_size (art, artist, type) {
	window.open('/artist/artwork/full_size.html?art=' + art + '&artist=' + artist + '&type=' + type + '','mywindow','width=550,height=550,toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=yes,copyhistory=yes,resizable=yes');
} // end full_size

function preview(art, size) {
	if (size == "fullsize") window.open('/artist/artwork/preview.html?art=' + art + '&size=' + size, 'art_' + art + '_' + size, 'width=550,height=550,toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=yes,copyhistory=yes,resizable=yes');
	else window.open('/artist/artwork/preview.html?art=' + art + '&size=' + size, 'art_' + art + '_' + size, 'width=300,height=350,toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=yes,copyhistory=yes,resizable=yes');
	
} // end fullsize

function allDigits(str) {return inValidCharSet(str,"0123456789");}

function validRequired(formField,fieldLabel) {
	var result = true;
	
	if (formField.value == "") {
		alert('Please enter a value for the "' + fieldLabel +'" field.');
		formField.focus();
		result = false;
	}
	
	return result;
}

function inValidCharSet(str,charset) {
	var result = true;

	// Note: doesn't use regular expressions to avoid early Mac browser bugs	
	for (var i=0;i<str.length;i++) {
		if (charset.indexOf(str.substr(i,1))<0){
			result = false;
			break;
		}
	} // end for
	
	return result;
}

function validNum(formField,fieldLabel) {
	var result = true;

	if (!validRequired(formField,fieldLabel))
		result = false;
  
    // this is needed to prevent 'too much recursion' or 'overflowing stack' errors on FireFox or IE
 	if (formField.value.charAt(0) == '0') {
 		alert('Please enter a valid number for the "' + fieldLabel +'" field.');
 		formField.focus();
 		result = false;
 	} // end if
	 
	if (result) {
 		if (!allDigits(formField.value)) {
 			alert('Please enter a number for the "' + fieldLabel +'" field.');
			formField.focus();		
			result = false;
		}
	} 
	
	return result;
}

/*
verifies that Firstname, Lastname are filled in (check boxes are handled by sign_up.html)
*/
function signup_verify () {
	if (document.sign_up.firstname.value=="") {
		alert ("You must enter your first name to sign up.");	
	} // end if
	else if (document.sign_up.lastname.value=="") {
		alert ("You must enter your last name to sign up.");
	} // end else if
	else if (document.sign_up.email.value=="") {
		alert ("You must enter your email to sign up.");
	} // end else if
	else {
		document.sign_up.action='sign_up.html';
		document.sign_up.submit();
	} // end else
} // end signup_verify

/*
verifies quantity field to make sure it is a positive integer
*/
function submit_add (form) {
	if (validNum (form.quantity, 'Quantity')) {
		form.action='add.html';
		form.submit();
	} // end if
} // end submit_add