//validation functions

function checkForm()
{
    //validate yourname
    if (document.form1.txtYourName.value == "")
    {
        alert("Please type your name");
        document.form1.txtYourName.focus();
        return false;
    }
    
    //validate youremail
    if (document.form1.txtYourEmail.value == "")
    {
        alert("Please type your email address");
        document.form1.txtYourEmail.focus();
        return false;
    }

    //validate youremail
    if (isValidEmail(document.form1.txtYourEmail.value)==false)
    {
        alert("Please type your valid email address");
        document.form1.txtYourEmail.select();
        return false;
    }
    
    //validate friends name
    if (document.form1.txtFriendName.value == "")
    {
        alert("Please type your friend's name");
        document.form1.txtFriendName.focus();
        return false;
    }
    
    //validate friendemail
    if (document.form1.txtFriendEmail.value == "")
    {
        alert("Please type your friend's email address");
        document.form1.txtFriendEmail.focus();
        return false;
    }

    //validate friendemail
    if (isValidEmail(document.form1.txtFriendEmail.value)==false)
    {
        alert("Please type your friend's valid email address");
        document.form1.txtFriendEmail.select();
        return false;
    }    
    
    //validate message
    if (document.form1.txtMessage.value == "")
    {
        alert("Please type your message");
        document.form1.txtMessage.focus();
        return false;
    }    
    
    
    return true;
}


function isValidEmail(str) 
{
   return (str.indexOf(".") > 2) && (str.indexOf("@") > 0);
}