//**dataURL to blob**    function dataURLtoBlob(dataurl) {        var arr = dataurl.split(','), mime = arr[0].match(/:(.*?);/)[1],            bstr = atob(arr[1]), n = bstr.length, u8arr = new Uint8Array(n);        while (n--) {            u8arr[n] = bstr.charCodeAt(n);        }        return new Blob([u8arr], { type: mime });    }    //**blob to dataURL**    function blobToDataURL(blob, callback) {        var a = new FileReader();        a.onload = function (e) { callback(e.target.result); }        a.readAsDataURL(blob);    }    //test:    //var blob = dataURLtoBlob('data:text/plain;base64,YWFhYWFhYQ==');    //blobToDataURL(blob, function (dataurl) {    //    console.log(dataurl);    //});