利用JavaScript检查用户注册信息是否正确，在以下情况不满足时报错并阻止提交表单

<!-- HTML结构 -->
<form id="test-register" action="#" target="_blank" onsubmit="return checkRegisterForm()">
<p id="test-error" style="color:red"></p>
<p>
用户名: <input type="text" id="username" name="username">
</p>
<p>
口令: <input type="password" id="password" name="password">
</p>
<p>
重复口令: <input type="password" id="password-2">
</p>
<p>
<button type="submit">提交</button> <button type="reset">重置</button>
</p>
</form>

//js部分

function checkRegisterForm(){
var usrname = document.getElementById('username');
var gz = /^[_0-9a-zA-Z]{3,10}$/;
var pwd1 = document.getElementById('password');
var pwd2 = document.getElementById('password-2');
if(gz.test(usrname.value) == true && (pwd1.value.length > 6 && pwd1.value.length < 20) && (pwd1.value == pwd2.value)){
return true;
}else{
return false;
}

}