使用js调用Gravatar头像，经过折腾是可行的，可是折腾了半天，又不想用了，于是先存起来备用。

<script language="javascript">

function get_avatar(email, size) {

function trim(str){

for (var i=0;(i<str.length)&&(str.charAt(i)==" ");++i) ;

for (var j=str.length;(j>0)&&(str.charAt(j-1)==" ");--j) ;

if (i>j) return "";

return str.substring(i,j);

}

noavatar = "http://1.gravatar.com/avatar/ad516503a11cd5ca435acc9bb6523536?s=" + size;

email.toLowerCase();

grav_url = "http://www.gravatar.com/avatar/" + hex_md5(trim(email)) + "?d="+encodeURI(noavatar) + "&s="+size;

return grav_url;

}

</SCRIPT>

==============================

其中size为头像的尺寸。

调用代码：document.getElementById("email").innerHTML="<img src=" +get_avatar(email, 40) +">";

另外需调用md5函数

<script type="text/javascript" src="md5.js"></script>

代码如下：

==============================

/*

* A JavaScript implementation of the RSA Data Security, Inc. MD5 Message

* Digest Algorithm, as defined in RFC 1321.

* Version 2.1 Copyright (C) Paul Johnston 1999 - 2002.

* Other contributors: Greg Holt, Andrew Kepert, Ydnar, Lostinet

* Distributed under the BSD License

* See http://pajhome.org.uk/crypt/md5 for more info.

*/

/*

* Configurable variables. You may need to tweak these to be compatible with

* the server-side, but the defaults work in most cases.

*/

var hexcase = 0; /* hex output format. 0 - lowercase; 1 - uppercase */

var b64pad = ""; /* base-64 pad character. "=" for strict RFC compliance */

var chrsz = 8; /* bits per input character. 8 - ASCII; 16 - Unicode */

/*

* These are the functions you´ll usually want to call

* They take string arguments and return either hex or base-64 encoded strings

*/

function hex_md5(s){ return binl2hex(core_md5(str2binl(s), s.length * chrsz));}

function b64_md5(s){ return binl2b64(core_md5(str2binl(s), s.length * chrsz));}

function str_md5(s){ return binl2str(core_md5(str2binl(s), s.length * chrsz));}

function hex_hmac_md5(key, data) { return binl2hex(core_hmac_md5(key, data)); }

function b64_hmac_md5(key, data) { return binl2b64(core_hmac_md5(key, data)); }

function str_hmac_md5(key, data) { return binl2str(core_hmac_md5(key, data)); }

/*

* Perform a simple self-test to see if the VM is working

*/

function md5_vm_test()

{

return hex_md5("abc") == "900150983cd24fb0d6963f7d28e17f72";

}

/*

* Calculate the MD5 of an array of little-endian words, and a bit length

*/

function core_md5(x, len)

{

/* append padding */

x[len >> 5] |= 0x80 << ((len) % 32);

x[(((len + 64) >>> 9) << 4) + 14] = len;

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 = md5_ff(a, b, c, d, x[i+ 0], 7 , -680876936);

d = md5_ff(d, a, b, c, x[i+ 1], 12, -389564586);

c = md5_ff(c, d, a, b, x[i+ 2], 17, 606105819);

b = md5_ff(b, c, d, a, x[i+ 3], 22, -1044525330);

a = md5_ff(a, b, c, d, x[i+ 4], 7 , -176418897);

d = md5_ff(d, a, b, c, x[i+ 5], 12, 1200080426);

c = md5_ff(c, d, a, b, x[i+ 6], 17, -1473231341);

b = md5_ff(b, c, d, a, x[i+ 7], 22, -45705983);

a = md5_ff(a, b, c, d, x[i+ 8], 7 , 1770035416);

d = md5_ff(d, a, b, c, x[i+ 9], 12, -1958414417);

c = md5_ff(c, d, a, b, x[i+10], 17, -42063);

b = md5_ff(b, c, d, a, x[i+11], 22, -1990404162);

a = md5_ff(a, b, c, d, x[i+12], 7 , 1804603682);

d = md5_ff(d, a, b, c, x[i+13], 12, -40341101);

c = md5_ff(c, d, a, b, x[i+14], 17, -1502002290);

b = md5_ff(b, c, d, a, x[i+15], 22, 1236535329);

a = md5_gg(a, b, c, d, x[i+ 1], 5 , -165796510);

d = md5_gg(d, a, b, c, x[i+ 6], 9 , -1069501632);

c = md5_gg(c, d, a, b, x[i+11], 14, 643717713);

b = md5_gg(b, c, d, a, x[i+ 0], 20, -373897302);

a = md5_gg(a, b, c, d, x[i+ 5], 5 , -701558691);

d = md5_gg(d, a, b, c, x[i+10], 9 , 38016083);

c = md5_gg(c, d, a, b, x[i+15], 14, -660478335);

b = md5_gg(b, c, d, a, x[i+ 4], 20, -405537848);

a = md5_gg(a, b, c, d, x[i+ 9], 5 , 568446438);

d = md5_gg(d, a, b, c, x[i+14], 9 , -1019803690);

c = md5_gg(c, d, a, b, x[i+ 3], 14, -187363961);

b = md5_gg(b, c, d, a, x[i+ 8], 20, 1163531501);

a = md5_gg(a, b, c, d, x[i+13], 5 , -1444681467);

d = md5_gg(d, a, b, c, x[i+ 2], 9 , -51403784);

c = md5_gg(c, d, a, b, x[i+ 7], 14, 1735328473);

b = md5_gg(b, c, d, a, x[i+12], 20, -1926607734);

a = md5_hh(a, b, c, d, x[i+ 5], 4 , -378558);

d = md5_hh(d, a, b, c, x[i+ 8], 11, -2022574463);

c = md5_hh(c, d, a, b, x[i+11], 16, 1839030562);

b = md5_hh(b, c, d, a, x[i+14], 23, -35309556);

a = md5_hh(a, b, c, d, x[i+ 1], 4 , -1530992060);

d = md5_hh(d, a, b, c, x[i+ 4], 11, 1272893353);

c = md5_hh(c, d, a, b, x[i+ 7], 16, -155497632);

b = md5_hh(b, c, d, a, x[i+10], 23, -1094730640);

a = md5_hh(a, b, c, d, x[i+13], 4 , 681279174);

d = md5_hh(d, a, b, c, x[i+ 0], 11, -358537222);

c = md5_hh(c, d, a, b, x[i+ 3], 16, -722521979);

b = md5_hh(b, c, d, a, x[i+ 6], 23, 76029189);

a = md5_hh(a, b, c, d, x[i+ 9], 4 , -640364487);

d = md5_hh(d, a, b, c, x[i+12], 11, -421815835);

c = md5_hh(c, d, a, b, x[i+15], 16, 530742520);

b = md5_hh(b, c, d, a, x[i+ 2], 23, -995338651);

a = md5_ii(a, b, c, d, x[i+ 0], 6 , -198630844);

d = md5_ii(d, a, b, c, x[i+ 7], 10, 1126891415);

c = md5_ii(c, d, a, b, x[i+14], 15, -1416354905);

b = md5_ii(b, c, d, a, x[i+ 5], 21, -57434055);

a = md5_ii(a, b, c, d, x[i+12], 6 , 1700485571);

d = md5_ii(d, a, b, c, x[i+ 3], 10, -1894986606);

c = md5_ii(c, d, a, b, x[i+10], 15, -1051523);

b = md5_ii(b, c, d, a, x[i+ 1], 21, -2054922799);

a = md5_ii(a, b, c, d, x[i+ 8], 6 , 1873313359);

d = md5_ii(d, a, b, c, x[i+15], 10, -30611744);

c = md5_ii(c, d, a, b, x[i+ 6], 15, -1560198380);

b = md5_ii(b, c, d, a, x[i+13], 21, 1309151649);

a = md5_ii(a, b, c, d, x[i+ 4], 6 , -145523070);

d = md5_ii(d, a, b, c, x[i+11], 10, -1120210379);

c = md5_ii(c, d, a, b, x[i+ 2], 15, 718787259);

b = md5_ii(b, c, d, a, x[i+ 9], 21, -343485551);

a = safe_add(a, olda);

b = safe_add(b, oldb);

c = safe_add(c, oldc);

d = safe_add(d, oldd);

}

return Array(a, b, c, d);

}

/*

* These functions implement the four basic operations the algorithm uses.

*/

function md5_cmn(q, a, b, x, s, t)

{

return safe_add(bit_rol(safe_add(safe_add(a, q), safe_add(x, t)), s),b);

}

function md5_ff(a, b, c, d, x, s, t)

{

return md5_cmn((b & c) | ((~b) & d), a, b, x, s, t);

}

function md5_gg(a, b, c, d, x, s, t)

{

return md5_cmn((b & d) | (c & (~d)), a, b, x, s, t);

}

function md5_hh(a, b, c, d, x, s, t)

{

return md5_cmn(b ^ c ^ d, a, b, x, s, t);

}

function md5_ii(a, b, c, d, x, s, t)

{

return md5_cmn(c ^ (b | (~d)), a, b, x, s, t);

}

/*

* Calculate the HMAC-MD5, of a key and some data

*/

function core_hmac_md5(key, data)

{

var bkey = str2binl(key);

if(bkey.length > 16) bkey = core_md5(bkey, key.length * chrsz);

var ipad = Array(16), opad = Array(16);

for(var i = 0; i < 16; i++)

{

ipad[i] = bkey[i] ^ 0x36363636;

opad[i] = bkey[i] ^ 0x5C5C5C5C;

}

var hash = core_md5(ipad.concat(str2binl(data)), 512 + data.length * chrsz);

return core_md5(opad.concat(hash), 512 + 128);

}

/*

* Add integers, wrapping at 2^32. This uses 16-bit operations internally

* to work around bugs in some JS interpreters.

*/

function safe_add(x, y)

{

var lsw = (x & 0xFFFF) + (y & 0xFFFF);

var msw = (x >> 16) + (y >> 16) + (lsw >> 16);

return (msw << 16) | (lsw & 0xFFFF);

}

/*

* Bitwise rotate a 32-bit number to the left.

*/

function bit_rol(num, cnt)

{

return (num << cnt) | (num >>> (32 - cnt));

}

/*

* Convert a string to an array of little-endian words

* If chrsz is ASCII, characters >255 have their hi-byte silently ignored.

*/

function str2binl(str)

{

var bin = Array();

var mask = (1 << chrsz) - 1;

for(var i = 0; i < str.length * chrsz; i += chrsz)

bin[i>>5] |= (str.charCodeAt(i / chrsz) & mask) << (i%32);

return bin;

}

/*

* Convert an array of little-endian words to a string

*/

function binl2str(bin)

{

var str = "";

var mask = (1 << chrsz) - 1;

for(var i = 0; i < bin.length * 32; i += chrsz)

str += String.fromCharCode((bin[i>>5] >>> (i % 32)) & mask);

return str;

}

/*

* Convert an array of little-endian words to a hex string.

*/

function binl2hex(binarray)

{

var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";

var str = "";

for(var i = 0; i < binarray.length * 4; i++)

{

str += hex_tab.charAt((binarray[i>>2] >> ((i%4)*8+4)) & 0xF) +

hex_tab.charAt((binarray[i>>2] >> ((i%4)*8 )) & 0xF);

}

return str;

}

/*

* Convert an array of little-endian words to a base-64 string

*/

function binl2b64(binarray)

{

var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

var str = "";

for(var i = 0; i < binarray.length * 4; i += 3)

{

var triplet = (((binarray[i >> 2] >> 8 * ( i %4)) & 0xFF) << 16)

| (((binarray[i+1 >> 2] >> 8 * ((i+1)%4)) & 0xFF) << 8 )

| ((binarray[i+2 >> 2] >> 8 * ((i+2)%4)) & 0xFF);

for(var j = 0; j < 4; j++)

{

if(i * 8 + j * 6 > binarray.length * 32) str += b64pad;

else str += tab.charAt((triplet >> 6*(3-j)) & 0x3F);

}

}

return str;

}