Token

guid.js

function guid() {
    function hex(len) {
        var s = '', n = len || 4;
        while (s.length < n) {
            s += (((1+Math.random())*0x10000)|0).toString(16).substring(1);
        }
        return s.substr(0, n);
    }
    return [hex(8), hex(4), hex(4), hex(4), hex(12)].join('-');
}

token.js

function token(n){
    var salt = 'abcdefghijklmnopqrstuvwxyz0123456789', key = '', len = n || 6, length = salt.length, i = 0;
    if (length < len) {
    	while(salt.length < len) {
    		salt += salt;
    	}
    	length = salt.length;
    }
    for (; i<len; key+=salt.charAt(Math.floor(Math.random()*length)), i++);
    return key;
}

token.php

<?php

function token($len = 6) {
	$salt = 'abcdefghijklmnopqrstuvwxyz0123456789';
	if (strlen($salt) < $len) {
		while (strlen($salt) < $len) {
			$salt .= $salt;
		}
	}	
	return substr(str_shuffle($salt), 0, $len);
}

?>