（转载）javascript客户端生成MD5值的函数代码

（转载）http://www.jb51.net/article/26223.htm

用js实现的客户端即可实现md5值的代码，一般情况下都是后台语言才有的，客户端也有了，方便有需要的朋友了。

测试代码:

/* 
* A JavaScript implementation of the RSA Data Security, Inc. MD5 Message 
* Digest Algorithm, as defined in RFC 1321. 
* Copyright (C) Paul Johnston 1999 - 2000. 
* Updated by Greg Holt 2000 - 2001. 
* See http://pajhome.org.uk/site/legal.html for details. 
*/ 
var hex_chr = "0123456789abcdef"; 
function rhex(num) 
{ 
    str = ""; 
    for(var j = 0; j <= 3; j++) 
    str += hex_chr.charAt((num >> (j * 8 + 4)) & 0x0F) + 
    hex_chr.charAt((num >> (j * 8)) & 0x0F); 
    return str; 
} 
function str2blks_MD5(str) 
{ 
    nblk = ((str.length + 8) >> 6) + 1; 
    blks = new Array(nblk * 16); 
    for(var i = 0; i < nblk * 16; i++) blks[i] = 0; 
    for(var i = 0; i < str.length; i++) 
    blks[i >> 2] |= str.charCodeAt(i) << ((i % 4) * 8); 
    blks[i >> 2] |= 0x80 << ((i % 4) * 8); 
    blks[nblk * 16 - 2] = str.length * 8; 
    return blks; 
} 
function add(x, y) 
{ 
    var lsw = (x & 0xFFFF) + (y & 0xFFFF); 
    var msw = (x >> 16) + (y >> 16) + (lsw >> 16); 
    return (msw << 16) | (lsw & 0xFFFF); 
} 
function rol(num, cnt) 
{ 
    return (num << cnt) | (num >>> (32 - cnt)); 
} 
function cmn(q, a, b, x, s, t) 
{ 
    return add(rol(add(add(a, q), add(x, t)), s), b); 
} 
function ff(a, b, c, d, x, s, t) 
{ 
    return cmn((b & c) | ((~b) & d), a, b, x, s, t); 
} 
function gg(a, b, c, d, x, s, t) 
{ 
    return cmn((b & d) | (c & (~d)), a, b, x, s, t); 
} 
function hh(a, b, c, d, x, s, t) 
{ 
    return cmn(b ^ c ^ d, a, b, x, s, t); 
} 
function ii(a, b, c, d, x, s, t) 
{ 
    return cmn(c ^ (b | (~d)), a, b, x, s, t); 
} 
function MD5(str) 
{ 
    x = str2blks_MD5(str); 
    var a = 1732584193; 
    var b = -271733879; 
    var c = -1732584194; 
    var d = 271733878; 
    for(var i = 0; i < x.length; i += 16) 
    { 
        var olda = a; 
        var oldb = b; 
        var oldc = c; 
        var oldd = d; 
        a = ff(a, b, c, d, x[i+ 0], 7 , -680876936); 
        d = ff(d, a, b, c, x[i+ 1], 12, -389564586); 
        c = ff(c, d, a, b, x[i+ 2], 17, 606105819); 
        b = ff(b, c, d, a, x[i+ 3], 22, -1044525330); 
        a = ff(a, b, c, d, x[i+ 4], 7 , -176418897); 
        d = ff(d, a, b, c, x[i+ 5], 12, 1200080426); 
        c = ff(c, d, a, b, x[i+ 6], 17, -1473231341); 
        b = ff(b, c, d, a, x[i+ 7], 22, -45705983); 
        a = ff(a, b, c, d, x[i+ 8], 7 , 1770035416); 
        d = ff(d, a, b, c, x[i+ 9], 12, -1958414417); 
        c = ff(c, d, a, b, x[i+10], 17, -42063); 
        b = ff(b, c, d, a, x[i+11], 22, -1990404162); 
        a = ff(a, b, c, d, x[i+12], 7 , 1804603682); 
        d = ff(d, a, b, c, x[i+13], 12, -40341101); 
        c = ff(c, d, a, b, x[i+14], 17, -1502002290); 
        b = ff(b, c, d, a, x[i+15], 22, 1236535329); 
        a = gg(a, b, c, d, x[i+ 1], 5 , -165796510); 
        d = gg(d, a, b, c, x[i+ 6], 9 , -1069501632); 
        c = gg(c, d, a, b, x[i+11], 14, 643717713); 
        b = gg(b, c, d, a, x[i+ 0], 20, -373897302); 
        a = gg(a, b, c, d, x[i+ 5], 5 , -701558691); 
        d = gg(d, a, b, c, x[i+10], 9 , 38016083); 
        c = gg(c, d, a, b, x[i+15], 14, -660478335); 
        b = gg(b, c, d, a, x[i+ 4], 20, -405537848); 
        a = gg(a, b, c, d, x[i+ 9], 5 , 568446438); 
        d = gg(d, a, b, c, x[i+14], 9 , -1019803690); 
        c = gg(c, d, a, b, x[i+ 3], 14, -187363961); 
        b = gg(b, c, d, a, x[i+ 8], 20, 1163531501); 
        a = gg(a, b, c, d, x[i+13], 5 , -1444681467); 
        d = gg(d, a, b, c, x[i+ 2], 9 , -51403784); 
        c = gg(c, d, a, b, x[i+ 7], 14, 1735328473); 
        b = gg(b, c, d, a, x[i+12], 20, -1926607734); 
        a = hh(a, b, c, d, x[i+ 5], 4 , -378558); 
        d = hh(d, a, b, c, x[i+ 8], 11, -2022574463); 
        c = hh(c, d, a, b, x[i+11], 16, 1839030562); 
        b = hh(b, c, d, a, x[i+14], 23, -35309556); 
        a = hh(a, b, c, d, x[i+ 1], 4 , -1530992060); 
        d = hh(d, a, b, c, x[i+ 4], 11, 1272893353); 
        c = hh(c, d, a, b, x[i+ 7], 16, -155497632); 
        b = hh(b, c, d, a, x[i+10], 23, -1094730640); 
        a = hh(a, b, c, d, x[i+13], 4 , 681279174); 
        d = hh(d, a, b, c, x[i+ 0], 11, -358537222); 
        c = hh(c, d, a, b, x[i+ 3], 16, -722521979); 
        b = hh(b, c, d, a, x[i+ 6], 23, 76029189); 
        a = hh(a, b, c, d, x[i+ 9], 4 , -640364487); 
        d = hh(d, a, b, c, x[i+12], 11, -421815835); 
        c = hh(c, d, a, b, x[i+15], 16, 530742520); 
        b = hh(b, c, d, a, x[i+ 2], 23, -995338651); 
        a = ii(a, b, c, d, x[i+ 0], 6 , -198630844); 
        d = ii(d, a, b, c, x[i+ 7], 10, 1126891415); 
        c = ii(c, d, a, b, x[i+14], 15, -1416354905); 
        b = ii(b, c, d, a, x[i+ 5], 21, -57434055); 
        a = ii(a, b, c, d, x[i+12], 6 , 1700485571); 
        d = ii(d, a, b, c, x[i+ 3], 10, -1894986606); 
        c = ii(c, d, a, b, x[i+10], 15, -1051523); 
        b = ii(b, c, d, a, x[i+ 1], 21, -2054922799); 
        a = ii(a, b, c, d, x[i+ 8], 6 , 1873313359); 
        d = ii(d, a, b, c, x[i+15], 10, -30611744); 
        c = ii(c, d, a, b, x[i+ 6], 15, -1560198380); 
        b = ii(b, c, d, a, x[i+13], 21, 1309151649); 
        a = ii(a, b, c, d, x[i+ 4], 6 , -145523070); 
        d = ii(d, a, b, c, x[i+11], 10, -1120210379); 
        c = ii(c, d, a, b, x[i+ 2], 15, 718787259); 
        b = ii(b, c, d, a, x[i+ 9], 21, -343485551); 
        a = add(a, olda); 
        b = add(b, oldb); 
        c = add(c, oldc); 
        d = add(d, oldd); 
    } 
    return rhex(a) + rhex(b) + rhex(c) + rhex(d); 
}