function checkProceedingsForm(theForm) {
   var why = "";
   why += checkFirstName(theForm.firstname.value);
   why += checkFamilyName(theForm.familyname.value);
   why += checkTitle(theForm.title.value);
   why += checkEmail(theForm.email.value);
   why += checkAddress(theForm.address.value);
   why += checkContrTitle(theForm.contrtitle.value);
   why += checkContrFile(theForm.contrfile.value);
   why += checkContrType(theForm.contrtype.value);

   if(why != ""){
     alert(why);
     return false;
   }
   return true;
}
/* ----------------------------------------------------- */
function checkFirstName(strng){
   var error="";
   if(strng == "") {
     error = "Please provide your first name.\n"; 
   } 
   return error;
}
/* ----------------------------------------------------- */
function checkFamilyName(strng){
   var error="";
   if(strng == "") {
     error = "Please provide your family name.\n"; 
   }
   return error;
}
/* ----------------------------------------------------- */
function checkTitle(strng){
   var error="";
   if(strng == "") {
     error = "Please provide your title.\n";
   }
   return error;
}
/* ----------------------------------------------------- */
function checkAddress(strng){
   var error="";
   if(strng == "") {
     error = "Please provide your institution address.\n";
   }
   return error;
}
/* ----------------------------------------------------- */
function checkContrTitle(strng){
   var error="";
   if(strng == "") {
     error = "Please provide the title of your contribution.\n";
   }
   return error;
}
/* ----------------------------------------------------- */
function checkContrType(strng){
   var error="";
   if(strng == "") {
     error = "Please provide the type of your contribution.\n";
   }
   return error;
}
/* ----------------------------------------------------- */
function checkContrFile(strng){
   var error="";
   if(strng == "") {
     error = "Please provide a file to upload.\n";
   }
   return error;
}
/* ----------------------------------------------------- */
function checkEmail(strng){
   var emailFilter=/^.+@.+\..+$/;
   var error="";
   if(!(emailFilter.test(strng))){
      error = "Please enter a valid email adress.\n";
   }
   return error;
}