registration form html javascript code example

Example 1: login and registration form

Some of the codes that can help :
1. https://codepen.io/ehermanson/pen/KwKWEv
2. https://codepen.io/trangsihung/pen/zbwGx
3. https://codepen.io/Mhmdhasan/pen/JbJzZv
4. https://codepen.io/suez/pen/RpNXOR

Example 2: javascript login validation

<script language = "JavaScript">
        function validate() {
            var username = document.getElementById("username").value;
            var password = document.getElementById("password").value;
            if (username == null || username == "") {
                alert("Please enter the username.");
                return false;
            }
            if (password == null || password == "") {
                alert("Please enter the password.");
                return false;
            }
            alert('Login successful');
            
        } 
</script>