function leeg_veld(field) {
	with (field) {
		if (value==null||value=="") {return true;}
		else {return false;}
}	}

function exceeds_250(field) {
	with (field) {
		if (value==null||value=="") {return false;}
		else if (value.length > 250) {return true;}
		else {return false;}
}	}

function Email_Check(Estr){			// NB: the period "." is replaced by a hash "#" to avoid metacharacter problems
	var regex = '^';				// Start of line
	regex += '[-_a-z0-9]+';     	// Name: One or more underscore, alphanumeric, or hyphen characters
 	regex += '(#[-_a-z0-9]+)*';	// Followed by zero or more sets of a period and one or more underscore, alphanumeric, or hyphen characters
	regex += '@';					// "at" characture
	regex += '[-a-z0-9]+';			// Domain: one or more alphanumeric or hyphen characters
	regex += '(#[a-z0-9]{2,6})?';	// Toplevel domain: optional e.g. museum, travel
	regex += '(#[a-z0-9]{2,4})+';	// Country: one or more sets consisting of a period and two to four alphanumeric characters.
	regex += '$';					// End of line
	var pattern=new RegExp(regex,"i");

	if ((Estr == "") || (Estr == null)) {return false;}
	if (Estr.match(/\s/i) != null) {return false;}		// check for spaces
	if (pattern.test(Estr.replace(/\./ig,"#"))) {return true;}
	return false;
}