我在控制台上遇到“未捕获类型错误”

Question

我想使用Fire Base身份验证来身份验证并将数据提交到数据库。我遇到这个错误

“未捕获的TypeError：userFirstName.match不是函数”

我想知道我在做错什么，以及可以采取的解决措施。

function checkUserFirstName(){
    var userSurname = document.getElementById("userFirstName").value;
    var flag = false;
    if(userSurname === ""){
        flag = true;
    }
     if(flag){
         document.getElementById("userFirstNameError").style.display = "block";
     }else{
        document.getElementById("userFirstNameError").style.display = "none";
    }
}
function checkUserSurname(){
    var userSurname = document.getElementById("userSurname").value;
    var flag = false;
    if(userSurname === ""){
        flag = true;
    }
    if(flag){
        document.getElementById("userSurnameError").style.display = "block";
     }else{
        document.getElementById("userSurnameError").style.display = "none";
     }
}
function checkUserEmail(){
    var userEmail = document.getElementById("userEmail");
    var userEmailFormate = /^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;
    var flag;
    if(userEmail.value.match(userEmailFormate)){
        flag = false;
    }else{
        flag = true;
    }
    if(flag){
         document.getElementById("userEmailError").style.display = "block";
     }else{
         document.getElementById("userEmailError").style.display = "none";
     }
}

function checkUserPassword(){
    var userPassword = document.getElementById("userPassword");
    var userPasswordFormate = /(?=.*\d)(?=.*[a-z])(?=.*[A-Z]).{10,}/;      
    var flag;
    if(userPassword.value.match(userPasswordFormate)){
        flag = false;
    }else{
        flag = true;
    }    
    if(flag){
        document.getElementById("userPasswordError").style.display = "block";
     }else{
         document.getElementById("userPasswordError").style.display = "none";
     }
}
function signUp(){
    var userFirstName = document.getElementById("userFirstName");
    var userSurname = document.getElementById("userSurname");
    var userEmail = document.getElementById("userEmail");
    var userPassword = document.getElementById("userPassword");
    var userFirstNameFormate = /^([A-Za-z.\s_-])/;    
    var userEmailFormate = /^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;
    var userPasswordFormate = /(?=.*\d)(?=.*[a-z])(?=.*[A-Z]).{10,}/;