Detecting CRLF with Javascript

Question

Hello everyone and thanks for the help in advance. I am working with an Asp.Net Core page that accepts the data into a <textarea> from a QR code scanner. When the scanner sends the data to the page, there is clearly some time of hidden line break after the input. I then tried redirecting the scanned input to Notepad++ and the end of the line shows CR|LF. I tried

        if ($("#txtqrcodescan").val().indexOf("/\r\n") !== -1) {
            alert("CR/LF detected");
        }

But this doesn't work. I also tried it without the escape character without success. Any help would be appreciated.