Extract Image name from JavaScript and save in database in ASP.Net

Article: Write JavaScript function in Code Behind in ASP.Net using C# and VB.Net

how do i extract the image name from the javascript and save it in the database using code behind

this is the script

<script type="text/javascript">
    function Send(element) {
        var imageName = document.getElementById('myimg').getElementsByTagName('img')[0].src = element.src;
        //var imageName = document.getElementById("imgFlag").src.split('/')[document.getElementById("imgFlag").src.split('/').length - 1];

        var a = imageName.split("/");
        var a_length = a.length - 1;
        var aa = a[a_length];
        var url = "Gown_Details.aspx?img=" + encodeURIComponent(aa);

        window.location.href = url;
    }
</script>