Q:

If and Else Statements Always Output If

I was messing around with a previously existing snippet and ran into an issue.
Whenever I try to enter an input that doesn't apply the to If statement it always gives me the If output. Also I was looking to, instead of saying approved, have you sent to a URL, like Google for example, and I'm not sure about a solution for either of the two.

function myFunction() {
  var a = document.getElementById("text_a").value;

  if (a == "02035", "02048", "02067") {
    document.getElementById("answer").innerHTML = "Approved";
  } else {
    document.getElementById("answer").innerHTML = "Our service currently isn't available in your area! Try again soon!";
  }
}
<p>Enter Zip Code </p>
<input id="text_a" type="text" />
<p id="answer"></p>
<button onclick="myFunction()">Check</button>

A:

if (a=="02035","02048","02067")

You can't do like this. 
There are many ways to check it. You could do like this
function myFunction() {
  var a = document.getElementById("text_a").value;
  var list = ["02035", "02048", "02067"];
  console.log(a)
  if ((list.indexOf(a) > -1)) {
    document.getElementById("answer").innerHTML = "Approved";
  } else {
    document.getElementById("answer").innerHTML =
      "Our service currently isn't available in your area! Try again soon!";
  }
}

I made a sample:  https://codepen.io/anon/pen/bWBvMj?editors=1011

