var number = 5;
    var url = "http://google.com";
    var redirected = false;

    function DetectDownload() {
        var newDiv = $('<div id="box" />').text("");
        var downloadUrl = $(".download").parent("a").attr('href');
        if (downloadUrl != undefined) {
            var extension = downloadUrl.substr((downloadUrl.lastIndexOf('.') + 1));
            if (extension == 'pdf') { // check file is a PDF
                downloadUrl = 'DownloadFile.aspx?File=' + downloadUrl;
                $(".download").parent("a").after(newDiv);
                url = downloadUrl;
                countdown();
            }
        }
    }

    function countdown() {
        
        setTimeout(countdown, 1000);
        $('#box').html("<p class='dl_count'>Your download will start in " + number + " seconds. <br /><a href='" + url + "'>Manual Download</a></p>");
        number--;
        if (number < 0 && redirected == false) {
            window.location = url;
            number = 0;
            redirected = true;
        }
        else if (redirected == true) {
            number = 0; 
        }
    }
    
   
 $(document).ready(function () {
        DetectDownload();
    });