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JavaScript Regular Expressions in JavaScript Validating a Form Form Validation

amarpreet singh saluja
amarpreet singh saluja
1,053 Points

Error saying it matches other values. can you help me understand

// Type inside this function function isValidHex(text) { const hexRegEx= /#([A-F0-9]{3}|[A-F0-9]{3})/i; return hexRegEx.test(text); }

app.js
// Type inside this function
function isValidHex(text) {
  const hexRegEx= /#([A-F0-9]{3}|[A-F0-9]{3})/i;
    return hexRegEx.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)";
  }
});
index.html
<!DOCTYPE html>
<html>

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

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

</html>

1 Answer

Steven Parker
Steven Parker
229,787 Points

This regex will match anything that begins with a pound sign and 3 hex characters. So while an RGB code will match, there are many other things that are not valid RGB codes that will also match.

Some hints for creating a valid regex:

  • it should match when six and only six hex values follow the pound sign
  • grouping the RGB characters (with parentheses) is not necessary