function checkfields(){
	var str = "";
	
	if (document.jform.company.value == "" ) {
		str = str + " Company Name\n";
	}	
	if (document.jform.last_name.value == "" ) {
		str = str + " Contact Person \n";
	}
	if (document.jform.position.value == "" ) {
		str = str + " Function \n";
	}	
	if (document.jform.postal_address.value == "" ) {
		str = str + " Postal Address \n";
	}	
	if (document.jform.zip_place.value == "" ) {
		str = str + " Zip Code /Place \n";
	}	
	if (document.jform.personnel.value == "" ) {
		str = str + " Number of employees \n";
	}
			
	if (document.jform.digi.value=="") {
		str = str + " E-mail\n";
	}else if ( document.jform.digi.value.length > 0 && ( document.jform.digi.value.indexOf("@",0) == -1 || document.jform.digi.value.indexOf(".",0) == -1 ) ) {
			str += " a valid email \n"	;
	}
			
	 if(str == ""){
		  document.jform.action = "join_form_companies.php";
		  document.jform.submit();
	 }
	 else {
			alert("please fill in :\n" + str);
	 }
}