const regex = /((?:ht|f)tps?:\/\/(\w+\.\w{2}[\/\w-.]*))/gi;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('((?:ht|f)tps?:\\\/\\\/(\\w+\\.\\w{2}[\\\/\\w-.]*))', 'gi')
const str = `http://matthiasweiss.at/asd/asd
ftp://hallo.welt
https://hallowelt.jpg
http://asdasd.aa/jojoji.jiji
mail@matthiasweiss.at
http://matthiasweiss.at
`;
const subst = `<a href="$1">$1</a>`;
// The substituted value will be contained in the result variable
const result = str.replace(regex, subst);
console.log('Substitution result: ', result);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions