//----Form validating-----------------------------
function check_email(mail){
	var pos1; var pos2; var pos3;
	pos1 = mail.indexOf('.');
	pos2 = mail.indexOf('@');
	pos3 = mail.indexOf(' ');
	if(pos1<0 || pos2<0 || pos3>0) return false;
	return true;
}

function validating_required(form_elm,compare){
/*
	Ham nhan vao array cac form element (vd document.f1.name) va gia tri can so sanh
	-> Tra ve true neu tat ca elm thoa (!=compare)
	-> Tra ve mot array chua cac form_elm khong thoa
*/
	var invalid = new Array();
	for(i=0;i<form_elm.length;i++){
		if(form_elm[i].value==compare)
			invalid.push(form_elm[i]);
	}
	if(invalid.length>0) return invalid;			
	else return true;
}

function multi_select(val_arr,obj){
	/*
		Ham nhan vao mot arr va multiselect object, se selected cac item co val trong array
	*/
	
	for(i=0;i<val_arr.length;i++){
		for(j=0;j<obj.length;j++){
			if(obj[j].value==val_arr[i]){
				obj[j].selected=true;
				break;
			}
		}
	}
}

function checkbox_checkall(obj,checklist){
	if(obj.checked) mycheck = true;
	else mycheck = false;
	for(i=0;i<checklist.length;i++)
		checklist[i].checked = mycheck;
}

function check_num(obj,length,e){
	var key = window.event ? e.keyCode : e.which;
	var len = obj.value.length + 1;
	if(length<=3) begin=48; else begin = 45;
	if(key>=begin && key<=57 && len <= length || (key==8 || key==0)){
		/*var keychar = String.fromCharCode(key);			
		reg = /\d/;
		return reg.test(keychar);*/
	}
	else return false;
}
function check_length(obj,length,e){
	var key = window.event ? e.keyCode : e.which;
	var len = obj.value.length + 1;
	if(len <= length || (key==8 || key==0)){}
	else return false;
}