（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);
}