function check_it()
{
 var complete=true;
 var thename=document.f1.xFirstName.value;
 var thenamel=document.f1.xLastName.value;
 var content=document.f1.xComment.value;
 var email_ad=document.f1.xMail.value;

 if ((thename=="") || (thename == null))
{
alert("Enter 'Name'");
complete= false;
}
 if ((thenamel=="") || (thenamel == null))
{
alert("Enter 'Family name'");
complete= false;
}
if ((content=="") || (content == null))
{
alert("Enter 'Your inquiry to us'");
complete= false;
}
if ((email_ad.indexOf("@") ==-1) || (email_ad.indexOf(".") ==-1))
{
   alert ("Enter valid e-mail address");
   complete= false;
}

return complete;
}