If you make a <input type="url">
maybe I’ll fix it.
But if you want in javascript, here’s an example:
<html>
<head>
<script src="https://code.jquery.com/jquery-3.3.1.min.js" integrity="sha256-FgpCb/KJQlLNfOu91ta32o/NMZxltwRo8QtmkMRdAu8=" crossorigin="anonymous"></script>
</head>
<body>
<form class="form">
<input type="text" id="url">
<button type="submit">Enviar</button>
</form>
<script>
function checkurl(str)
{
regexp = /^(?:(?:https?):\/\/)?(?:(?!(?:10|127)(?:\.\d{1,3}){3})(?!(?:169\.254|192\.168)(?:\.\d{1,3}){2})(?!172\.(?:1[6-9]|2\d|3[0-1])(?:\.\d{1,3}){2})(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)(?:\.(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)*(?:\.(?:[a-z\u00a1-\uffff]{2,})))(?::\d{2,5})?(?:\/\S*)?$/;
if (regexp.test(str))
{
alert("Endereco ok");
return true;
}
else
{
alert("Insira um endereco valido.");
return false;
}
}
</script>
<script>
$('.form').on('submit', function () {
var url = document.getElementById("url").value;
checkurl(url);
});
</script>
</body>
</html>