verify integer value in javascript
<p>In my application, I am taking a value for username.  If that value is 0, then I have to run some code.  But how should I write the if block?</p>

<pre><code> var userName=document.getElementById("member").value;
</code></pre>

<p>The above statement will return 0 (zero).  Can anybody write the if statement for me?  Thank you in advance.This is the entire code</p>

<pre><code>var userName=document.getElementById("member").value;
    var password=document.getElementById("password").value;

    if(userName==="0"){
        var div4 = document.getElementById("errorMessage");
        var text1 = "insert userName.";
        div4.style.display = "block";
        div4.style.color = "red";
        div4.style.fontSize = "65%";
        div4.innerHTML = text1;
</code></pre>
