function isEmail(elm) {
	if (elm.value.indexOf("@") != "-1" && elm.value.indexOf(".") != "-1" || elm.value == "")
	return true;
    else return false;
}

function checkForm(formobj) {

var errors = new Array();
var ok = true;
	if (formobj.email.value == '') {
		errors.push('Please enter your email address.');
		ok=false;
	}
	if (formobj.email.value != '') {
		if (isEmail(formobj.email) == false) {
			errors.push ('The email address you entered appears to be invalid.');
        	ok=false;
		}
	}

	
if (errors.length > 0) {
	alert(errors.join("\n"));
}
	
return ok;
}