// form validation for onsubmit
function validateForm(frm,fields,labels,mssg) {
	// params: frm = name of form, fields = array of field names to be checked, labels = array of field labels, lang = interface language
	// note: fields + labels should be parallel and same length -> fields[0] -> labels[0] etc.
	var back = true;
	var out = "";
	for(var i=0;i<fields.length;i++) {
		fname = 'user_runners_pi1['+fields[i]+']';
		// check type of input field:
		var etype = document.forms[frm].elements[fname].type;
		if ( etype == 'select-one' ) {
			if ( document.forms[frm].elements[fname].options[document.forms[frm].elements[fname].selectedIndex].value == '' ) {
				out += "- "+labels[i] + "\n";
				back = false;
			}
		}
		else if ( etype == 'text' || etype == 'textarea' ) {
			if ( document.forms[frm].elements[fname].value == '' ) {
				out += "- "+labels[i] + "\n";
				back = false;
			}
		}
	}
	if ( ! back ) alert(mssg+"\n"+out);
	return back;
}



// form validation for onsubmit; for forms with non-specific-fieldnames, with validation of e-mail-address (basic syntax and confirmation)
function validateFormStd(frm,fields,labels,mssg,mssgEmail) {
	// params: frm = name of form, fields = array of field names to be checked, labels = array of field labels, mssg = general errormessage, mssEmail = specific errormessage for e-mail-validation
	// note: fields + labels should be parallel and same length -> fields[0] -> labels[0] etc.
	//to check and confirm e-mail-address, fields have to be named 'email' and 'email2'
	var back = true;
	var out = "";
	for(var i=0;i<fields.length;i++) {
		fname = fields[i];
		// check type of input field:
		var etype = document.forms[frm].elements[fname].type;
		if ( etype == 'select-one' ) {
			if ( document.forms[frm].elements[fname].options[document.forms[frm].elements[fname].selectedIndex].value == '' ) {
				out += "- "+labels[i] + "\n";
				back = false;
			}
		}
		else if ( etype == 'text' || etype == 'textarea' ) {
			if ( document.forms[frm].elements[fname].value == '' ) {
				out += "- "+labels[i] + "\n";
				back = false;
			}
		}
	}
	if ( ! back ) alert(mssg+"\n"+out);
 	  else if (((document.forms[frm].email.value.indexOf ('@', 0) == -1) || (document.forms[frm].email.value.indexOf ('.', 0) == -1)) || (document.forms[frm].email.value != document.forms[frm].email2.value))  {
  	    alert(mssgEmail);
		return false;
  	  }
	return back;
}