Validate A Form With Javascript Before Submitting With Ajax?

I've been making a website and I want a nice login/registration/forgot pass form. I wanted to use 'ajax' to make it nice for the user and, consequently, have spent the last 2 weeks

Solution 1:

<form id="loginFormID" onsubmit="return validateLoginFormOnSubmit();" method="post" autocomplete="on">

JavaScript

funciton validateLoginFormOnSubmit() {

        //do client side validation 

        if(true == validation) {
             //do the `ajax` call with serialized form data
        }
        else {
            //show error 
        }

        return false; // because we want to submit only through `ajax`, so stopping original form submit.
}