Web

HTML5 Color Input Value

Validate the value of an HTML5 `<input type="color">` — exactly 6 hex digits with leading hash.

Available in

JavaScript / ECMAScript code

jsJavaScript

const re = new RegExp("^#[0-9a-fA-F]{6}$", "");
const input = "#ff5733";
const matches = [...input.matchAll(re)];
console.log(matches.map(m => m[0]));

Uses `String.prototype.matchAll` for global iteration (Node 12+ / all modern browsers).

Python (re) code

pyPython

import re

pattern = re.compile(r"^#[0-9a-fA-F]{6}$")
input_text = "#ff5733"
for m in pattern.finditer(input_text):
    print(m.group(0))

Stdlib `re` module — no third-party dependency. Works on Python 3.6+.

Go (RE2) code

goGo

package main

import (
	"fmt"
	"regexp"
)

func main() {
	re := regexp.MustCompile(`^#[0-9a-fA-F]{6}$`)
	input := `#ff5733`
	for _, match := range re.FindAllString(input, -1) {
		fmt.Println(match)
	}
}

Uses `regexp.MustCompile` (panics on bad patterns at startup) and `FindAllString` for all matches.

Pattern

regexengine-agnostic

^#[0-9a-fA-F]{6}$

Raw source: ^#[0-9a-fA-F]{6}$

How it works

^# requires the leading hash. [0-9a-fA-F]{6} requires exactly 6 hexadecimal digits. $ anchors the end. Note this is STRICTER than the general hex-color pattern: the HTML5 color input only accepts the 6-digit form, not the 3-digit shorthand.