Exported HTML table to excel giving warning while opening the file using office Excel

I am trying to export HTML table to xls format. But when I try to open the file using Excel, I am given a warning message. The waring message:

I using this lines of code:

var file = new Blob([ html.outerHTML], {
            type: "application/vnd.ms-excel"
        });
        var url = URL.createObjectURL(file);
        var filename = dateSelected + "-" + "attendance" + ".xls"

        //here we are creating HTML <a> Tag which can be trigger to download the excel file.
        var a = document.createElement('a');
        a.id = "export";
        document.body.appendChild(a);
        //here we are checking if the bwoswer is IE or not if IE then we use window.navigator.msSaveBlob function otherwise Go with Simple Blob file.
        if (window.navigator && window.navigator.msSaveBlob) {
            window.navigator.msSaveBlob(file, filename);
            a.click();
            document.body.removeChild(a);
            document.body.removeChild(html);
        } else {
            a.download = filename;
            a.href = url;
            a.click();
            document.body.removeChild(a);
            document.body.removeChild(html);
        }

I tried to change the blob type but nothing is working. How can i solve this issue?

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