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JavaScript Regular Expressions in JavaScript Validating a Form Form Validation

amarpreet singh saluja
amarpreet singh saluja
1,053 Points
Posted by 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
231,261 Points
Steven Parker
Steven Parker
231,261 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