/**
 * login validation check & submit.
 * @return
 */
function fn_login() {
	var fm = document.loginFm;
	
	var userId = fm.user_id;
	var userPw = fm.user_pw;

	if(userId.value.trim() == '') {
		alert('아이디를 입력해주십시오.');
		return false;
	}
	if(userPw.value.trim() == '') {
		alert('비밀번호를 입력해주십시오.');
		return false;
	}

	fm.action = '/_inc/loginPrc.jsp';
	fm.target = '_self';

	return true;
}

/**
 * 탭 layer display control
 * @param displayId
 * @param hideId
 * @return
 */
function fn_tabDisplayControl(displayId, hideId) {
	var displayElem = document.getElementById(displayId);
	var hideElem    = document.getElementById(hideId);
	
	hideElem.style.display    = 'none';
	displayElem.style.display = 'block';	
}

/**
 * input element 의 background image 설정
 * @param elem
 * @param src
 * @return
 */
function fn_setBackground(elem, src) {
	if(elem.value == '' || elem.value == null) {
		elem.style.backgroundImage = 'url(\''+src+'\')';
	}
}

/**
 * input element 의 background image 제거
 * @param elem
 * @return
 */
function fn_clearBackground(elem) {
	elem.style.backgroundImage = 'none';
}