// Check for valid email address: look for @ and .
function isEmail(elm) {
    if (elm.value.indexOf("@") != "-1" &&
        elm.value.indexOf(".") != "-1") {
        return true;
    }
    else {
        return false;
    }
}

// Check for blank fields
function isFilled(elm) {
    if (elm.value == "" || elm.value == null) {
        return false;
    }
    else {
        return true;
    }
}


// Show Error
function showErr(errmsg) {
        var layer = document.getElementById(errmsg);
        //layer.style.display = "block";
        layer.style.visibility = "visible";
}
// Hide Error
function hideErr(errmsg) {
        var layer = document.getElementById(errmsg);
        //layer.style.display = "none";
        layer.style.visibility = "hidden";
}

// Check entire form
function bookingVal(form) {

    if (isFilled(form.name) == false) {        // name
        //alert("Please enter your name.");
        showErr("name_err");
 		form.name.focus();      
        return false;
    }
    else {
    	hideErr("name_err");
    }

    if (isEmail(form.email) == false) {          // email address
        //alert("Please enter a valid email address.");
        showErr("email_err");
        form.email.focus();
        return false;
    }
    else {
    	hideErr("email_err");
    }
  
    if (isFilled(form.message) == false) {         // message
        //alert("Please enter a message.");
        showErr("message_err");
        form.message.focus();
        return false;
    }
    else {
    	hideErr("message_err");
    }

   
}