This a simple javascript function to validate the name and password as our requirements before the user submit the form.

In this i have used the Regex To create my requirements 

Name Validation

function userNameValidation(usernameInput) {
    var issueArr = [];
    if (/[[email protected]#$%^&*()_+|~=`{}\[\]:";'<>?,.\/]/.test(usernameInput)) {
        issueArr.push("No special characters!");
    }

    return issueArr;
}

Password Validation

function passwordValidation(passwordInput) {
    var issueArr = [];
    if (!/^.{6,8}$/.test(passwordInput)) {
        issueArr.push("Password must be between 6-8 characters.");
    }
    if (!/\d/.test(passwordInput)) {
        issueArr.push("Must contain at least one number.");
    }
    if (!/[a-z]/.test(passwordInput)) {
        issueArr.push("Must contain a lowercase letter.");
    }
    if (!/[A-Z]/.test(passwordInput)) {
        issueArr.push("Must contain an uppercase letter.");
    }
    return issueArr;
}

Then Using the HTMLSelectElement.setCustomValidity()  method sets the custom validity message for the selection element to the specified message.

You can run the html file to see the output.

I am a beginner so you can suggest me any thing that i can work on.

Thanks.