无法将文本框输入转换为整数？

Question

我正在尝试创建一个程序，该程序接受用户输入的数字并将其与随机生成的数字进行比较，直到用户猜出正确的数字。我遇到了一个问题，当我调试程序时，我的用户输入号码显示为未定义，但我使用了 parseInt 并解决了该问题。现在看来这是我的 if else 语句的问题，因为当我对代码运行调试时，我现在得到了正确的使用输入编号，但现在当我运行它时，即使我输入 1000 作为我的猜测，它总是给出我“你的猜测太低了！尝试更大的数字。”

var guessNum;//user input guess


function randomNumber(guessNum1)
{

    guessNum = document.getElementById( "numInput" ).value;//getting value of user input
    var guessNum1 = parseInt(guessNum);//change user input to integer
    
    var num = Math.floor( 1 + Math.random() * 1000 ); //random number generator 
    
    if (num == guessNum1)
    {
        messages.innerHTML = "Congratulations! You guessed the number!";
    
    }
        else if (num < guessNum1)
        {
            messages.innerHTML = "Your guess is too high! Try a lower number.";
        }
            else (num > guessNum1)
            {
                messages.innerHTML = "Your guess is too low! Try a higher number.";
            }
    
    guessNum = document.getElementById( "numInput" ).value = "";//clears the textbox on screen
            
}

function start()
{
    var guessButton = document.getElementById( "guess" );//variable for clicking button
    guessButton.addEventListener( "click", randomNumber, false);
    //event listener for button that starts randomNumber function
    messages = document.getElementById( "messages" );
}

window.addEventListener( "load", start, false);//starts start function on screen load

<h1>Guess the Number!</h1>

<h3>Enter in a number between 1-1000 in the textbox and hit submit </h3>

<form action = "#">
    <input id= "numInput" type="text" >
    <input id= "guess" type="button" value="Guess" > 
</form>

<p id= "messages">Enter a number to start the game </p>