本文实例讲述了JavaScript实现MD5算法的方法。分享给大家供大家参考，具体如下：

/** * * MD5 (Message-Digest Algorithm) * / * **/ var MD5 = function (string) { function RotateLeft(lValue, iShiftBits) { return (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) 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