var user_name = document.getElementById('username').value;
var input_password = document.getElementById('password').value;
var confirm_password = document.getElementById('password-2').value;
var error = document.getElementById('test-error');
error.innerText = '';

console.log('user_name: ' + user_name);
console.log('input_password: ' + input_password);
console.log('confirm_password: ' + confirm_password);

var re_username = /^[a-zA-Z0-9]{3,10}$/;
var re_password = /^.{6,20}$/;

if(!re_username.test(user_name)) {
    error.innerText = '用户名必须是3-10位英文字母或数字';
    return false;
}
if(!re_password.test(input_password)) {
    error.innerText = '口令必须是6-20位';
    return false;
}
if(input_password !== confirm_password) {
    error.innerText = '两次输入口令必须一致';
    return false;
}
return true;