js版md5算法：

/**
*
*  MD5 (Message-Digest Algorithm)
*  http://www.webtoolkit.info/
*
**/var MD5 = function (string) {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) {string = string.replace(/\r\n/g,"\n");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;};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.toLowerCase();
};console.log(MD5('12341234'));