如果没有顶级域名，则在不使用协议或www的情况下验证网址的字符串

Question

I am trying to validate user input strings for valid URL. I am able to test for strings that either have an http(s):// or www. Here is my code:

var urlRegEx = /((([A-Za-z]{3,9}:(?:\/\/)?)(?:[\-;:&=\+\$,\w]+@)?[A-Za-z0-9\.\-]+|(?:www\.|[\-;:&=\+\$,\w]+@)[A-Za-z0-9\.\-]+)((?:\/[\+~%\/\.\w\-]*)?\??(?:[\-\+=&;%@\.\w]*)#?(?:[\.\!\/\\\w]*))?)/g;
if(urlRegEx.test(str)){
  alert('Valid URL');
}else{
    alert('Invalid URL');
}

It works fine, even for cases like https://google.co.in/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=list%20of%20all%20top%20level%20domains

However, it does not validate abc.com or domain-name.tld

I would want it to work something like Whatsapp, where any string followed by a ".", followed by a top level domain, gets converted to a url but other strings don't. For example, abc.com, abc.net, abc.au etc., all get converted to URLs. However, abc.anything, won't get converted to URL. Even this: abc.au?kgfjhg#kjhkjh=jkhkjh/kjdhkjd is identified as a URL at Whatsapp.

Answer 1

Sure, here is an example javascript regex:

^[a-zA-Z]{3,9}\.(com|au|org)[^a-zA-Z]

What it does: It matches something that starts with 3 to 9 alphabet characters, then a dot ("."), and then one of several known top level domains (com|au|org) which is a list that you can expand, followed by, if anything, a non-alphabet character (so that com and com/x will be valid top level domains, but comx will not be valid).

Note this is not a regex to match standard URLs.

Btw I used this site to write and test the regex live, maybe you'll find it useful.

If you'd like more features for the regex, feel free to comment and I'll add them

Enjoy!