最近遇到了一個比較奇葩的問題，字符串-->base64，但是里邊還涉及到了gbk編碼問題，代碼如下：var content_base64 = "CgkJCgkJCQk8Y29uZGl0aW9ucyB0eXBlPSJBTkQiPgoJCQkJCTxzeXNDb25kaXRpb25zIHR5cGU9Inx8Ij4KCQkJCQk8c3lzQ29uZGl0aW9uIG5hbWU9ItDCzsS1tSIgZXhwcmVzc2lvbj0iS0dselRtVjNSRzlqS0NrcElBPT0iLz4KCQkJCQk8c3lzQ29uZGl0aW9uIG5hbWU9IrWxx7C0psDtyMsiIGV4cHJlc3Npb249IktHbHpRM1Z5VlhObGNpZ3BLU0E9Ii8+CgkJCQkJPC9zeXNDb25kaXRpb25zPgoJCQkJPC9jb25kaXRpb25zPgoJCQk=";var arrayBuffer = _base64ToArrayBuffer(content_base64);var content = new TextDecoder("gbk").decode(arrayBuffer);console.log(content);function _base64ToArrayBuffer(base64) {    var binary_string =  window.atob(base64);    var len = binary_string.length;    var bytes = new Uint8Array( len );    for (var i = 0; i < len; i++)        {        bytes[i] = binary_string.charCodeAt(i);    }    return bytes.buffer;}function _arrayBufferToBase64( buffer ) {    var binary = '';    var bytes = new Uint8Array( buffer );    var len = bytes.byteLength;    for (var i = 0; i < len; i++) {        binary += String.fromCharCode( bytes[ i ] );    }    return window.btoa( binary );}怎么把字符串再轉(zhuǎn)回base64(gbk編碼格式)???