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JavaScript Regular Expressions in JavaScript Validating a Form Form Validation

Can someone please help me out with this problem. I don't understand what I am doing wrong.

It is saying that my variable isn't holding a regex expression.

// Type inside this function
function isValidHex(text) {
  const hexRegEx = /^#[A-F][a-f][0-7]$/i.test(text);

const hex = document.getElementById("hex");
const body = document.getElementsByTagName("body")[0];

hex.addEventListener("input", e => {
  const text = e.target.value;
  const valid = isValidHex(text);
  if (valid) {
    body.style.backgroundColor = "rgb(176, 208, 168)";
  } else {
    body.style.backgroundColor = "rgb(189, 86, 86)";
<!DOCTYPE html>

    <title>DOM Manipulation</title>
<link rel="stylesheet" href="style.css" />

    <div id="content">
        <p>Enter a valid hex value below to make the screen turn green.</p>
        <input type="text" id="hex">
    <script src="app.js"></script>


1 Answer

Brendan Whiting
.a{fill-rule:evenodd;}techdegree seal-36
Brendan Whiting
Front End Web Development Techdegree Graduate 84,734 Points

They want you to just start by assigning a regular expression to the variable hexRegEx. Don't call the test() method on it yet. Your code as it is right now will actually assign a boolean value to hexRegEx, the result of calling test().

While we're at it, there are a few other things your regex will need to do to meet the requirements:

  • the letters and numbers will not necessarily be in this order
  • there will be exactly 6 characters after the # symbol
  • we need to include the digits 8 & 9 as well as 0-7
  • FYI if you're using the case insensitive flag, you don't need to also check for both a-f and A-F

Let me know if you have more questions.