how to check if the input 42 to length long and must have 0x at the beginning

<html lang="en-US" class="lang-en" dir="ltr">
    <head>
        <meta http-equiv="X-UA-Compatible" content="IE=edge" />
        <meta name="viewport" content="width=device-width,initial-scale=1" />
        <script type="text/javascript" src="https://code.jquery.com/jquery-3.6.0.min.js"></script>
    </head>
    <body>
        <input type="text" id="check" data-minlength="42" name="address" onKeyDown="onInputKeyDown" />
        <button class="button button-rounded-rectangle" type="button" id="kato" disabled>Continue</button>
        <script type="text/javascript">
            function onInputKeyDown() {
                var keycode = keyPressed(event);
                if(keycode == 32) {
                    return false;
                }
            }
            //<![CDATA[
            $(function () {
                $("#kato").prop("disabled", true);
                $("#check").on("input", function (e) {
                    var regexpr = /^0x[a-z0-9]*$/;
                    if (regexpr.test(this.value) && this.value.length === 42) {
                        $("#kato").prop("disabled", false);
                    } else {
                        $("#kato").prop("disabled", true);
                    }
                });
            });
        //]]>
        </script>
    </body>
</html>