function productPopup(id) {
	var url = 'product_popup.php?product=' + id;
	var comwin = window.open(url,'Help','width=650,height=616,scrollbars=no,resize=no');
	comwin.focus() ;
}

function productScheme( id) {
	var url = 'product_scheme.php?id=' + id;
	var comwin = window.open(url,'Help','width=650,height=616,scrollbars=no,resize=no');
	comwin.focus() ;
}

function checkQuantity() {
	var elem = document.getElementsByTagName("INPUT");
	if (elem != null) {
		for (i=0; i<elem.length; i++) {
			if (elem[i].name.indexOf('qty') != -1) {
				if (parseInt(elem[i].value)) {
					document.forms['cart'].submit();
				} else {
					alert('Please check quantity fields values');
					return false;
				}
			}
		}
	}
}

function coolRound(x) {
	var str= Math.round(x*100)/100+'';
	str = (str.charAt(0)=='.' ? '0'+str:str);
	if (str.charAt(str.length-3)=='.') {
		str+='';
	}
	else if (str.charAt(str.length-2)=='.') {
		str+='0';
	}
	else str+='.00';
	return str;
}

function calculateTotal(value) {
	totalSum = coolRound( (eval(parseFloat(prev) + parseFloat(tax) + parseFloat(value))) );
	
	total_val.innerHTML = totalSum;
}

function checkZip() {
	if ( (document.forms['calc'].ship_zip.value == '') ) {
		alert('Please check zip code value');
		return false;
	} else {
		document.forms['calc'].submit();
	}
}

function validateTextField(field) {
	if (field.length > 2) {
		return true;
	} else {
		return false;
	}
}

function validateNumberField(field) {
	if (!isNaN(field)) {
		if (field.length > 2) {
			return true;
		} else {
			return false;
		}
	} else {
		return false;
	}
}
	
function validateMail(str) {

	var at="@"
	var dot="."
	var lat=str.indexOf(at)
	var lstr=str.length
	var ldot=str.indexOf(dot)
	if (str.indexOf(at)==-1){
		return false
	}

	if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr){
		return false
	}

	if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr){
		return false
	}

	if (str.indexOf(at,(lat+1))!=-1){
		return false
	}

	if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){
		return false
	}

	if (str.indexOf(dot,(lat+2))==-1){
		return false
	}

	if (str.indexOf(" ")!=-1){
		return false
	}

	return true
}


function validateForm() {

	var msg = '';

	if (!validateTextField(document.forms['form'].your_name.value)) msg = '  * Error in Your Name field value;\n';
	if (!validateMail(document.forms['form'].your_mail.value)) msg += '  * Error in Your E-mail field value;\n';
	
	if (!validateTextField(document.forms['form'].friend_name.value)) msg += '  * Error in Friend Name field value;\n';
	if (!validateMail(document.forms['form'].friend_mail.value)) msg += '  * Error in Friend E-mail field value;\n';
	
	if (msg.length != 0) {
		msg = 'Some errors occuired:\n' + msg;
		alert(msg);
		return false;
	} else {
		document.forms['form'].submit();
	}

}