小程序MD5加密（支持中文）

function md5(string) {
    var x = Array();
    var k, AA, BB, CC, DD, a, b, c, d;
    var S11 = 7, S12 = 12, S13 = 17, S14 = 22;
    var S21 = 5, S22 = 9, S23 = 14, S24 = 20;
    var S31 = 4, S32 = 11, S33 = 16, S34 = 23;
    var S41 = 6, S42 = 10, S43 = 15, S44 = 21;
    string = Utf8Encode(string);
    x = ConvertToWordArray(string);
    a = 0x67452301;
    b = 0xEFCDAB89;
    c = 0x98BADCFE;
    d = 0x10325476;
    for (k = 0; k < x.length; k += 16) {
        AA = a;
        BB = b;
        CC = c;
        DD = d;
        a = FF(a, b, c, d, x[k + 0], S11, 0xD76AA478);
        d = FF(d, a, b, c, x[k + 1], S12, 0xE8C7B756);
        c = FF(c, d, a, b, x[k + 2], S13, 0x242070DB);
        b = FF(b, c, d, a, x[k + 3], S14, 0xC1BDCEEE);
        a = FF(a, b, c, d, x[k + 4], S11, 0xF57C0FAF);
        d = FF(d, a, b, c, x[k + 5], S12, 0x4787C62A);
        c = FF(c, d, a, b, x[k + 6], S13, 0xA8304613);
        b = FF(b, c, d, a, x[k + 7], S14, 0xFD469501);
        a = FF(a, b, c, d, x[k + 8], S11, 0x698098D8);
        d = FF(d, a, b, c, x[k + 9], S12, 0x8B44F7AF);
        c = FF(c, d, a, b, x[k + 10], S13, 0xFFFF5BB1);
        b = FF(b, c, d, a, x[k + 11], S14, 0x895CD7BE);
        a = FF(a, b, c, d, x[k + 12], S11, 0x6B901122);
        d = FF(d, a, b, c, x[k + 13], S12, 0xFD987193);
        c = FF(c, d, a, b, x[k + 14], S13, 0xA679438E);
        b = FF(b, c, d, a, x[k + 15], S14, 0x49B40821);
        a = GG(a, b, c, d, x[k + 1], S21, 0xF61E2562);
        d = GG(d, a, b, c, x[k + 6], S22, 0xC040B340);
        c = GG(c, d, a, b, x[k + 11], S23, 0x265E5A51);
        b = GG(b, c, d, a, x[k + 0], S24, 0xE9B6C7AA);
        a = GG(a, b, c, d, x[k + 5], S21, 0xD62F105D);
        d = GG(d, a, b, c, x[k + 10], S22, 0x2441453);
        c = GG(c, d, a, b, x[k + 15], S23, 0xD8A1E681);
        b = GG(b, c, d, a, x[k + 4], S24, 0xE7D3FBC8);
        a = GG(a, b, c, d, x[k + 9], S21, 0x21E1CDE6);
        d = GG(d, a, b, c, x[k + 14], S22, 0xC33707D6);
        c = GG(c, d, a, b, x[k + 3], S23, 0xF4D50D87);
        b = GG(b, c, d, a, x[k + 8], S24, 0x455A14ED);
        a = GG(a, b, c, d, x[k + 13], S21, 0xA9E3E905);
        d = GG(d, a, b, c, x[k + 2], S22, 0xFCEFA3F8);
        c = GG(c, d, a, b, x[k + 7], S23, 0x676F02D9);
        b = GG(b, c, d, a, x[k + 12], S24, 0x8D2A4C8A);
        a = HH(a, b, c, d, x[k + 5], S31, 0xFFFA3942);
        d = HH(d, a, b, c, x[k + 8], S32, 0x8771F681);
        c = HH(c, d, a, b, x[k + 11], S33, 0x6D9D6122);
        b = HH(b, c, d, a, x[k + 14], S34, 0xFDE5380C);
        a = HH(a, b, c, d, x[k + 1], S31, 0xA4BEEA44);
        d = HH(d, a, b, c, x[k + 4], S32, 0x4BDECFA9);
        c = HH(c, d, a, b, x[k + 7], S33, 0xF6BB4B60);
        b = HH(b, c, d, a, x[k + 10], S34, 0xBEBFBC70);
        a = HH(a, b, c, d, x[k + 13], S31, 0x289B7EC6);
        d = HH(d, a, b, c, x[k + 0], S32, 0xEAA127FA);
        c = HH(c, d, a, b, x[k + 3], S33, 0xD4EF3085);
        b = HH(b, c, d, a, x[k + 6], S34, 0x4881D05);
        a = HH(a, b, c, d, x[k + 9], S31, 0xD9D4D039);
        d = HH(d, a, b, c, x[k + 12], S32, 0xE6DB99E5);
        c = HH(c, d, a, b, x[k + 15], S33, 0x1FA27CF8);
        b = HH(b, c, d, a, x[k + 2], S34, 0xC4AC5665);
        a = II(a, b, c, d, x[k + 0], S41, 0xF4292244);
        d = II(d, a, b, c, x[k + 7], S42, 0x432AFF97);
        c = II(c, d, a, b, x[k + 14], S43, 0xAB9423A7);
        b = II(b, c, d, a, x[k + 5], S44, 0xFC93A039);
        a = II(a, b, c, d, x[k + 12], S41, 0x655B59C3);
        d = II(d, a, b, c, x[k + 3], S42, 0x8F0CCC92);
        c = II(c, d, a, b, x[k + 10], S43, 0xFFEFF47D);
        b = II(b, c, d, a, x[k + 1], S44, 0x85845DD1);
        a = II(a, b, c, d, x[k + 8], S41, 0x6FA87E4F);
        d = II(d, a, b, c, x[k + 15], S42, 0xFE2CE6E0);
        c = II(c, d, a, b, x[k + 6], S43, 0xA3014314);
        b = II(b, c, d, a, x[k + 13], S44, 0x4E0811A1);
        a = II(a, b, c, d, x[k + 4], S41, 0xF7537E82);
        d = II(d, a, b, c, x[k + 11], S42, 0xBD3AF235);
        c = II(c, d, a, b, x[k + 2], S43, 0x2AD7D2BB);
        b = II(b, c, d, a, x[k + 9], S44, 0xEB86D391);
        a = AddUnsigned(a, AA);
        b = AddUnsigned(b, BB);
        c = AddUnsigned(c, CC);
        d = AddUnsigned(d, DD);
    }
    var temp = WordToHex(a) + WordToHex(b) + WordToHex(c) + WordToHex(d);
    // return temp.toUpperCase();
    return temp.toLowerCase();
}
function RotateLeft(lValue, iShiftBits) {
    return (lValue << iShiftBits) | (lValue >>> (32 - iShiftBits));
}
function AddUnsigned(lX, lY) {
    var lX4, lY4, lX8, lY8, lResult;
    lX8 = (lX & 0x80000000);
    lY8 = (lY & 0x80000000);
    lX4 = (lX & 0x40000000);
    lY4 = (lY & 0x40000000);
    lResult = (lX & 0x3FFFFFFF) + (lY & 0x3FFFFFFF);
    if (lX4 & lY4) {
        return (lResult ^ 0x80000000 ^ lX8 ^ lY8);
    }
    if (lX4 | lY4) {
        if (lResult & 0x40000000) {
            return (lResult ^ 0xC0000000 ^ lX8 ^ lY8);
        } else {
            return (lResult ^ 0x40000000 ^ lX8 ^ lY8);
        }
    } else {
        return (lResult ^ lX8 ^ lY8);
    }
}
function F(x, y, z) {
    return (x & y) | ((~x) & z);
}
function G(x, y, z) {
    return (x & z) | (y & (~z));
}
function H(x, y, z) {
    return (x ^ y ^ z);
}
function I(x, y, z) {
    return (y ^ (x | (~z)));
}
function FF(a, b, c, d, x, s, ac) {
    a = AddUnsigned(a, AddUnsigned(AddUnsigned(F(b, c, d), x), ac));
    return AddUnsigned(RotateLeft(a, s), b);
}
function GG(a, b, c, d, x, s, ac) {
    a = AddUnsigned(a, AddUnsigned(AddUnsigned(G(b, c, d), x), ac));
    return AddUnsigned(RotateLeft(a, s), b);
}
function HH(a, b, c, d, x, s, ac) {
    a = AddUnsigned(a, AddUnsigned(AddUnsigned(H(b, c, d), x), ac));
    return AddUnsigned(RotateLeft(a, s), b);
}
function II(a, b, c, d, x, s, ac) {
    a = AddUnsigned(a, AddUnsigned(AddUnsigned(I(b, c, d), x), ac));
    return AddUnsigned(RotateLeft(a, s), b);
}
function ConvertToWordArray(string) {
    var lWordCount;
    var lMessageLength = string.length;
    var lNumberOfWords_temp1 = lMessageLength + 8;
    var lNumberOfWords_temp2 = (lNumberOfWords_temp1 - (lNumberOfWords_temp1 % 64)) / 64;
    var lNumberOfWords = (lNumberOfWords_temp2 + 1) * 16;
    var lWordArray = Array(lNumberOfWords - 1);
    var lBytePosition = 0;
    var lByteCount = 0;
    while (lByteCount < lMessageLength) {
        lWordCount = (lByteCount - (lByteCount % 4)) / 4;
        lBytePosition = (lByteCount % 4) * 8;
        lWordArray[lWordCount] = (lWordArray[lWordCount] | (string.charCodeAt(lByteCount) << lBytePosition));
        lByteCount++;
    }
    lWordCount = (lByteCount - (lByteCount % 4)) / 4;
    lBytePosition = (lByteCount % 4) * 8;
    lWordArray[lWordCount] = lWordArray[lWordCount] | (0x80 << lBytePosition);
    lWordArray[lNumberOfWords - 2] = lMessageLength << 3;
    lWordArray[lNumberOfWords - 1] = lMessageLength >>> 29;
    return lWordArray;
}
function WordToHex(lValue) {
    var WordToHexValue = "", WordToHexValue_temp = "", lByte, lCount;
    for (lCount = 0; lCount <= 3; lCount++) {
        lByte = (lValue >>> (lCount * 8)) & 255;
        WordToHexValue_temp = "0" + lByte.toString(16);
        WordToHexValue = WordToHexValue + WordToHexValue_temp.substr(WordToHexValue_temp.length - 2, 2);
    }
    return WordToHexValue;
}
function Utf8Encode(string) {
    var utftext = "";
    for (var n = 0; n < string.length; n++) {
        var c = string.charCodeAt(n);
        if (c < 128) {
            utftext += String.fromCharCode(c);
        } else if ((c > 127) && (c < 2048)) {
            utftext += String.fromCharCode((c >> 6) | 192);
            utftext += String.fromCharCode((c & 63) | 128);
        } else {
            utftext += String.fromCharCode((c >> 12) | 224);
            utftext += String.fromCharCode(((c >> 6) & 63) | 128);
            utftext += String.fromCharCode((c & 63) | 128);
        }
    }
    return utftext;
}