Javascript Phone Number Validation- error message erace

Question

Goal:

Phone number must be entered in this format, 208-111-1111; otherwise it shows the error message. What is the best way to show the error message when the user entered in the correct format but if the user re-entered in the correct format, the error message will disappear.

JS
phoneNumber = document.getElementById("phone");


var result = phoneNumber.toString().match(/^\d{3}-\d{3}-\d{4}$/);

function validatePhone(){
if (result == null)
{
error2.innerHTML = "The number is not in a correct format";
} else 
{
error2.innerHTML = " ";
};
}

HTML
<p>Phone:</p> 
      <input type = "text" id="phone" name="phone" onChange="validatePhone()">
      <br>
      <span id="error2" ></span>

Answer 1

 function validatePhone() { phoneNumber = document.getElementById("phone"); var result = phoneNumber.value.match(/^(\\d{3}-\\d{3}-\\d{4})?$/); if (result == null) { error2.innerHTML = "The number is not in a correct format"; } else { error2.innerHTML = " "; }; } 

 <p>Phone:</p> <input type="text" id="phone" name="phone" oninput="validatePhone()"> <br> <span id="error2"></span> 

Answer 2

The problem is with the phoneNumber.toString() call.

Calling toString() on a DOM input element does not return the value of the user input. toString() is intended to provide a string representation of the object it is called on, not retrieve a value held by the object.

phoneNumber.value will return the value you are looking for.