function PdfViewValid() {
    var browser_id = "";
    var pdf_view_valid = false;
    if (navigator) {
        var ualow = navigator.userAgent.toLowerCase();
        if (ualow.indexOf("msie") > -1) browser_id = "ie";
        else if (ualow.indexOf("chrome") > -1) browser_id = "chrome";
        else if (ualow.indexOf("firefox") > -1) browser_id = "firefox";
        else if (ualow.indexOf("mozilla") > -1) browser_id = "mozilla";
        else if (ualow.indexOf("opera") > -1) browser_id = "opera";
    }
    try {
        switch (browser_id) {
            case "ie":
                var ax = null;
                try {
                    ax = new ActiveXObject('AcroPDF.PDF');
                }
                catch (e) {
                }
                if (ax == null) {
                    try {
                        ax = new ActiveXObject('PDF.PdfCtrl');
                    }
                    catch (e) {
                    }
                }
                if (ax != null) {
                    pdf_view_valid = true;
                }
                break;
            case "chrome":
                for (key in navigator.plugins) {
                    if (typeof navigator.plugins[key].name != "undefined") {
                        if (navigator.plugins[key].name == "Chrome PDF Viewer" || navigator.plugins[key].name == "Adobe Acrobat") {
                            pdf_view_valid = true;
                            break;
                        }
                    }
                }
                break;
            default:
                var mac_os_agent = (navigator.userAgent.toLowerCase()).indexOf("mac os") > -1;
                var safari_agent = (navigator.userAgent.toLowerCase()).indexOf("safari") > -1;
                var webkit_builtin = /PDF.*WebKit/i;
                for (key in navigator.plugins) {
                    if (typeof navigator.plugins[key].name != "undefined") {
                        if (navigator.plugins[key].name.indexOf("Adobe Acrobat") == 0 || navigator.plugins[key].name.indexOf("Adobe Reader") == 0) {
                            pdf_view_valid = true;
                            break;
                        }
                        else if (mac_os_agent && safari_agent && webkit_builtin.test(navigator.plugins[key].name)) {
                            pdf_view_valid = true;
                            break;
                        }
                    }
                }
                break;
        }
    }
    catch (e) {
    }
    return pdf_view_valid;
}