用JS如何把utf8转换成Unicode

function Utf8ToUnicode(strUtf8) { var bstr = ""; var nTotalChars = strUtf8.length; // total chars to be processed. var nOffset = 0; // processing point on strUtf8 var nRemainingBytes = nTotalChars; // how many bytes left to be converted var nOutputPosition = 0; iCode, iCode1, iCode2; // the value of the unicode. while (nOffset < nTotalChars) { iCode = strUtf8.charCodeAt(nOffset); if ((iCode & 0x80) == 0) // 1 byte. { if (nRemainingBytes < 1) // not enough data break; bstr += String.fromCharCode(iCode & 0x7F); nOffset++; nRemainingBytes -= 1; } else if ((iCode & 0xE0) == 0xC0) // 2 bytes { iCode1 = strUtf8.charCodeAt(nOffset + 1); if (nRemainingBytes < 2 || // not enough data (iCode1 & 0xC0) != 0x80) // invalid pattern { break; } bstr += String .fromCharCode(((iCode & 0x3F) << 6) | (iCode1 & 0x3F)); nOffset += 2; nRemainingBytes -= 2; } else if ((iCode & 0xF0) == 0xE0) // 3 bytes { iCode1 = strUtf8.charCodeAt(nOffset + 1); iCode2 = strUtf8.charCodeAt(nOffset + 2); if (nRemainingBytes < 3 || // not enough data (iCode1 & 0xC0) != 0x80 || // invalid pattern (iCode2 & 0xC0) != 0x80) { break; } bstr += String.fromCharCode(((iCode & 0x0F) << 12) | ((iCode1 & 0x3F) << 6) | (iCode2 & 0x3F)); nOffset += 3; nRemainingBytes -= 3; } else // 4 or more bytes -- unsupported break; } if (nRemainingBytes != 0) { // bad UTF8 string. return ""; } return bstr; }