XMLHttpRequest.setRequestHeader test (source) Header x-test-1: süß Header name codepoints 00000078 0000002D 00000074 00000065 00000073 00000074 0000002D 00000031 Header value codepoints 00000073 000000FC 000000DF Header transmitted? true Transmitted header name bytes 78 2d 74 65 73 74 2d 31 Possible header name encoding ASCII UTF-8 Transmitted header value bytes 73 fc df Possible header value encoding unknown Header x-test-2: 中国 Header name codepoints 00000078 0000002D 00000074 00000065 00000073 00000074 0000002D 00000032 Header value codepoints 00004E2D 000056FD Header transmitted? true Transmitted header name bytes 78 2d 74 65 73 74 2d 32 Possible header name encoding ASCII UTF-8 Transmitted header value bytes 3f 3f Possible header value encoding unknown Header x-test-3: 𝌐 Header name codepoints 00000078 0000002D 00000074 00000065 00000073 00000074 0000002D 00000033 Header value codepoints 0001D310 Header transmitted? true Transmitted header name bytes 78 2d 74 65 73 74 2d 33 Possible header name encoding ASCII UTF-8 Transmitted header value bytes 3f 3f Possible header value encoding unknown Header x-test-4-süß: 4 Header name codepoints 00000078 0000002D 00000074 00000065 00000073 00000074 0000002D 00000034 0000002D 00000073 000000FC 000000DF Header value codepoints 00000034 Header transmitted? true Transmitted header name bytes 78 2d 74 65 73 74 2d 34 2d 73 fc df Possible header name encoding unknown Transmitted header value bytes 34 Possible header value encoding ASCII UTF-8 Header x-test-5-中国: 5 Header name codepoints 00000078 0000002D 00000074 00000065 00000073 00000074 0000002D 00000035 0000002D 00004E2D 000056FD Header value codepoints 00000035 Header transmitted? true Transmitted header name bytes 78 2d 74 65 73 74 2d 35 2d 3f 3f Possible header name encoding unknown Transmitted header value bytes 35 Possible header value encoding ASCII UTF-8 Header x-test-6-𝌐: 6 Header name codepoints 00000078 0000002D 00000074 00000065 00000073 00000074 0000002D 00000036 0000002D 0001D310 Header value codepoints 00000036 Header transmitted? true Transmitted header name bytes 78 2d 74 65 73 74 2d 36 2d 3f 3f Possible header name encoding unknown Transmitted header value bytes 36 Possible header value encoding ASCII UTF-8 Done.