function validate_required(field,alerttxt){
	var valid = false;
	myField = document.getElementById(field);
	with (myField){
		switch(type){
			case 'radio':
				radioValue=getRadioValue(myField);
				if (radioValue!=null&&radioValue!=""){valid=true;}
				break;
			case 'checkbox':
				if (checked==true){valid=true;}
				break;
			default:
				if (value!=null&&value!=""){valid=true}
				break;
		}
	}
	if (valid == false) { alert(alerttxt); myField.focus(); }
	return valid;
}
	
function getRadioValue(radioObj) {
	if(!radioObj)
		return "";
	radioArray = document.getElementsByName(radioObj.name);
	var radioLength = radioArray.length;
	for(var i = 0; i < radioLength; i++) {
		if(radioArray[i].checked) {
			return radioArray[i].value;
		}
	}
	return "";
}