var username = document.getElementById('username').value;
var pwd1 = document.getElementById('password').value;
var pwd2 = document.getElementById('password-2').value;
var reg1 = /^\w{3,10}$/;
var reg2 = /^.{6,20}$/;
if ( reg1.test(username) && reg2.test(pwd1) && pwd1===pwd2 ) {
    alert('success');
    return true;
}
return false;