如果你可以改变输入类型，我认为这个解决方案会更容易:

你可以简单地在输入中使用type="url"，并在js中使用checkValidity()检查它

E.g:

your.html

<input id="foo" type="url">

your.js

// The selector is JQuery, but the function is plain JS
$("#foo").on("keyup", function() {
    if (this.checkValidity()) {
        // The url is valid
    } else {
        // The url is invalid
    }
});

我将函数更改为Match +，在这里用斜杠和它的工作:(http://和https)进行更改

function isValidUrl(userInput) {
    var res = userInput.match(/(http(s)?:\/\/.)?(www\.)?[-a-zA-Z0-9@:%._\+~#=]{2,256}\.[a-z]{2,6}\b([-a-zA-Z0-9@:%_\+.~#?&//=]*)/g);
    if(res == null)
       return false;
    else
       return true;
}

这是@palvo的答案的扩展。

function isValidHttpUrl(string) {
  let url;
  try {
    url = new URL(string);
  } catch (_) {
    return false;  
  }
  return (url.protocol === "http:" || url.protocol === "https:") && (url.href == string || url.origin == string);
}

试试以下方法:-

isValidHttpUrl(“https:母羊/ dsdsd”); isValidHttpUrl(“https://ewe/dsdsd”);

Chrome测试

如果你想检查一个字符串是否是有效的HTTP URL，你可以使用URL构造函数(它会抛出一个畸形的字符串):

函数isValidHttpUrl(string) { 让url; 尝试{ url =新的url(字符串); } catch (_) { 返回错误; ｝ 返回的url。Protocol === "http:" || url。协议=== "https:"; ｝ console.log (" http://example.com " + isValidHttpUrl (" https://example.com ")); console.log (" example.com " + isValidHttpUrl (" example.com "));

注意:根据RFC 3886, URL必须以一个方案开头(不限于http/https)，例如:

www.example.com不是有效的URL(缺少方案) void(0)是有效的URL，但不是HTTP URL http://.。是有效的URL，主机是..(是否解析取决于你的DNS) https://example..com是有效的URL，与上面相同

对已接受答案的改进…

Check for ftp/ftps as protocol Has double escaping for backslashes (\\) Ensures that domains have a dot and an extension (.com .io .xyz) Allows full colon (:) in the path e.g. http://thingiverse.com/download:1894343 Allows ampersand (&) in path e.g http://en.wikipedia.org/wiki/Procter_&_Gamble Allows @ symbol in path e.g. https://medium.com/@techytimo isURL(str) { var pattern = new RegExp('^((ft|htt)ps?:\\/\\/)?'+ // protocol '((([a-z\\d]([a-z\\d-]*[a-z\\d])*)\\.)+[a-z]{2,}|'+ // domain name and extension '((\\d{1,3}\\.){3}\\d{1,3}))'+ // OR ip (v4) address '(\\:\\d+)?'+ // port '(\\/[-a-z\\d%@_.~+&:]*)*'+ // path '(\\?[;&a-z\\d%@_.,~+&:=-]*)?'+ // query string '(\\#[-a-z\\d_]*)?$','i'); // fragment locator return pattern.test(str); }

As has been noted the perfect regex is elusive but still seems to be a reasonable approach (alternatives are server side tests or the new experimental URL API). However the high ranking answers are often returning false for common URLs but even worse will freeze your app/page for minutes on even as simple a string as isURL('aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'). It's been pointed out in some of the comments, but most probably haven't entered a bad value to see it. Hanging like that makes that code unusable in any serious application. I think it's due to the repeated case insensitive sets in code like ((([a-z\\d]([a-z\\d-]*[a-z\\d])*)\\.?)+[a-z]{2,}|' .... Take out the 'i' and it doesn't hang but will of course not work as desired. But even with the ignore case flag those tests reject high unicode values that are allowed.

已经提到的最好的是:

function isURL(str) {
  return /^(?:\w+:)?\/\/([^\s\.]+\.\S{2}|localhost[\:?\d]*)\S*$/.test(str); 
}

That comes from Github segmentio/is-url. The good thing about a code repository is you can see the testing and any issues and also the test strings run through it. There's a branch that would allow strings missing protocol like google.com, though you're probably making too many assumptions then. The repository has been updated and I'm not planning on trying to keep up a mirror here. It's been broken up into separate tests to avoid RegEx redos which can be exploited for DOS attacks (I don't think you have to worry about that with client side js, but you do have to worry about your page hanging for so long that your visitor leaves your site).

在dperini/regex- webburl .js中，我还看到过另一个存储库，它可能更适合isURL，但它非常复杂。它有一个更大的有效和无效url的测试列表。上面的简单的一个仍然通过了所有的正面信息，只有一些奇怪的负面信息，如http://a.b--c.de/以及特殊的ip。

无论你选择哪一个，在使用浏览器的开发人员工具检查器时，通过这个函数运行它，这个函数是我从dperini/regex- webburl .js上的测试中改编的。

function testIsURL() {
//should match
console.assert(isURL("http://foo.com/blah_blah"));
console.assert(isURL("http://foo.com/blah_blah/"));
console.assert(isURL("http://foo.com/blah_blah_(wikipedia)"));
console.assert(isURL("http://foo.com/blah_blah_(wikipedia)_(again)"));
console.assert(isURL("http://www.example.com/wpstyle/?p=364"));
console.assert(isURL("https://www.example.com/foo/?bar=baz&inga=42&quux"));
console.assert(isURL("http://✪df.ws/123"));
console.assert(isURL("http://userid:password@example.com:8080"));
console.assert(isURL("http://userid:password@example.com:8080/"));
console.assert(isURL("http://userid@example.com"));
console.assert(isURL("http://userid@example.com/"));
console.assert(isURL("http://userid@example.com:8080"));
console.assert(isURL("http://userid@example.com:8080/"));
console.assert(isURL("http://userid:password@example.com"));
console.assert(isURL("http://userid:password@example.com/"));
console.assert(isURL("http://142.42.1.1/"));
console.assert(isURL("http://142.42.1.1:8080/"));
console.assert(isURL("http://➡.ws/䨹"));
console.assert(isURL("http://⌘.ws"));
console.assert(isURL("http://⌘.ws/"));
console.assert(isURL("http://foo.com/blah_(wikipedia)#cite-1"));
console.assert(isURL("http://foo.com/blah_(wikipedia)_blah#cite-1"));
console.assert(isURL("http://foo.com/unicode_(✪)_in_parens"));
console.assert(isURL("http://foo.com/(something)?after=parens"));
console.assert(isURL("http://☺.damowmow.com/"));
console.assert(isURL("http://code.google.com/events/#&product=browser"));
console.assert(isURL("http://j.mp"));
console.assert(isURL("ftp://foo.bar/baz"));
console.assert(isURL("http://foo.bar/?q=Test%20URL-encoded%20stuff"));
console.assert(isURL("http://مثال.إختبار"));
console.assert(isURL("http://例子.测试"));
console.assert(isURL("http://उदाहरण.परीक्षा"));
console.assert(isURL("http://-.~_!$&'()*+,;=:%40:80%2f::::::@example.com"));
console.assert(isURL("http://1337.net"));
console.assert(isURL("http://a.b-c.de"));
console.assert(isURL("http://223.255.255.254"));
console.assert(isURL("postgres://u:p@example.com:5702/db"));
console.assert(isURL("https://d1f4470da51b49289906b3d6cbd65074@app.getsentry.com/13176"));

//SHOULD NOT MATCH:
console.assert(!isURL("http://"));
console.assert(!isURL("http://."));
console.assert(!isURL("http://.."));
console.assert(!isURL("http://../"));
console.assert(!isURL("http://?"));
console.assert(!isURL("http://??"));
console.assert(!isURL("http://??/"));
console.assert(!isURL("http://#"));
console.assert(!isURL("http://##"));
console.assert(!isURL("http://##/"));
console.assert(!isURL("http://foo.bar?q=Spaces should be encoded"));
console.assert(!isURL("//"));
console.assert(!isURL("//a"));
console.assert(!isURL("///a"));
console.assert(!isURL("///"));
console.assert(!isURL("http:///a"));
console.assert(!isURL("foo.com"));
console.assert(!isURL("rdar://1234"));
console.assert(!isURL("h://test"));
console.assert(!isURL("http:// shouldfail.com"));
console.assert(!isURL(":// should fail"));
console.assert(!isURL("http://foo.bar/foo(bar)baz quux"));
console.assert(!isURL("ftps://foo.bar/"));
console.assert(!isURL("http://-error-.invalid/"));
console.assert(!isURL("http://a.b--c.de/"));
console.assert(!isURL("http://-a.b.co"));
console.assert(!isURL("http://a.b-.co"));
console.assert(!isURL("http://0.0.0.0"));
console.assert(!isURL("http://10.1.1.0"));
console.assert(!isURL("http://10.1.1.255"));
console.assert(!isURL("http://224.1.1.1"));
console.assert(!isURL("http://1.1.1.1.1"));
console.assert(!isURL("http://123.123.123"));
console.assert(!isURL("http://3628126748"));
console.assert(!isURL("http://.www.foo.bar/"));
console.assert(!isURL("http://www.foo.bar./"));
console.assert(!isURL("http://.www.foo.bar./"));
console.assert(!isURL("http://10.1.1.1"));}

然后测试这串a。

在你发布一个看起来很棒的正则表达式之前，看看Mathias Bynens对isURL正则表达式的比较，了解更多信息。