I want to track last updated changes in a html field and highlight the changes with different color.

Below is what I have tried:

content = fields.Html()

<record id="view_form" model="ir.ui.view">
        <field name="name">Formfield>
        <field name="model">module.modulefield>
        <field name="arch" type="xml">
            <form class="o_form">
                <script>
                    $(document).ready(function () {
                    $('.content-track').keyup(function () {
                    $(this).css({backgroundColor: "#333", color: "#FFF"});
                    });
                    });
                script>   
                <sheet>
                    <separator/>
                    <label for="content"/>
                    <field name="content" class="content-track"/>
                    <separator/>       
                sheet>  
            form>
        field>
    record>

But don't how to achieve it for last updated changes or if I can change the color of text whenever I type new content by default? And also I have issue in above code that whenever I refresh the page changes get removed.

Do anyone have any idea how to achieve this  and how to resolve the issue or any other idea to solve this?