var subonce;
function checkContact(){

                if(subonce == 1){
                                 alert("Please wait for the form to be submited");
                                 return false;
                                    }

                if         (    (document.contactform.name.value=="") 	 ||
                                (document.contactform.comment.value=="")        ||
                                (document.contactform.email.value=="")
                        		)
                        {
                                alert("You must fill all the fields marked with *.");
                                return false;
                        }
                else
                {
                        if (! isMail(document.contactform.email.value)        )
                                                {
                                                        alert('Your email does not seem to be valid.');
                                                        return false;
                                                }
                                        else
                                                {
                                                 subonce = 1;
                                                 return true;
                                                }

                }
                return false;
        }

// Check eMail
function isMail(sString) {
         var emailEXP = /^[a-z_0-9\.]+@[a-z_0-9\.]+\.[a-z]{2,3}$/i
     if (!sString.match(emailEXP)){
                 return false;
         }else{
                 return true;
         }
}// end eMail