JS URL 正则表达式判断

function isValidHttpUrl(string) {
  let url;

  try {
    url = new URL(string);
  } catch (_) {
    return false;
  }

  return url.protocol === 'http:' || url.protocol === 'https:';
}

function validURL(str) {
  var pattern = new RegExp(
    '^(https?:\\/\\/)?' + // protocol
      '((([a-z\\d]([a-z\\d-]*[a-z\\d])*)\\.)+[a-z]{2,}|' + // domain name
      '((\\d{1,3}\\.){3}\\d{1,3}))' + // OR ip (v4) address
      '(\\:\\d+)?(\\/[-a-z\\d%_.~+]*)*' + // port and path
      '(\\?[;&a-z\\d%_.~+=-]*)?' + // query string
      '(\\#[-a-z\\d_]*)?$',
    'i'
  ); // fragment locator
  return !!pattern.test(str);
}

参考资料

• https://stackoverflow.com/questions/5717093/check-if-a-javascript-string-is-a-url
• https://stackoverflow.com/questions/3809401/what-is-a-good-regular-expression-to-match-a-url