XML Namespace Declaration in JS
Match XML namespace declarations (`xmlns="..."` and `xmlns:prefix="..."`), capturing the prefix and URI.
Try it in the JS tester →Pattern
regexJS
xmlns(?::([\w\-]+))?\s*=\s*["']([^"']+)["'] (flags: g)JavaScript / ECMAScript code
jsJavaScript
const re = new RegExp("xmlns(?::([\\w\\-]+))?\\s*=\\s*[\"']([^\"']+)[\"']", "g");
const input = "<svg xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">";
const matches = [...input.matchAll(re)];
console.log(matches.map(m => m[0]));Uses `String.prototype.matchAll` for global iteration (Node 12+ / all modern browsers).
How the pattern works
xmlns matches the literal attribute name. (?::([\w\-]+))? optionally captures a colon-prefix (e.g. `xmlns:xlink`). \s*=\s* matches the equals with optional whitespace. ["']([^"']+)["'] captures the URI in either quote style.
Examples
Input
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">Matches
xmlns="http://www.w3.org/2000/svg"xmlns:xlink="http://www.w3.org/1999/xlink"
Input
<root xmlns='urn:custom'>Matches
xmlns='urn:custom'
Input
<plain>No match
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