By using the Data URI scheme you can embed images directly into your HTML and CSS. It works by encoding an image into a base64 string and place it directly withing an HTML image tag or as a CSS background URL. Such a base64 string url example in your CSS looks like this:

div.image {
 background: data:image/x-png;base64,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
}

I found this generator who generates such a string after uploading an image.
I used this for iPhone/iPad app development.

http://webcodertools.com/imagetobase64converter

I found a handy unicode converter online. This might become handy when for encoding UTF-8 characters in Javascript/JSON objects. (such as for example the € sign. which becomes: “\u20ac”

http://people.w3.org/rishida/scripts/uniview/conversion.php

In Joomla 1.5, you need to press the logout button within the login component, to log off your session.
This logic doesn’t seem very clear for me. If I want to log-off I don’t want 2 page clicks/refreshes.

To create a logout button or menu link, you just need to invoke the logout URL part:

index.php?option=com_user&task=logout&return=Lw==

Or incase when you have Search Engine Friendly (SEF) URL’s:

/logout.html?return=Lw

Now did you note, the return=Lw== parameter?
This parameter is for bringing you back to the return page, after logging out.
The “Lw==”-value, is a Base64 encoding for “/” which brings you back to the root of the page.

Say that you don’t want to forward to the root, but to the ‘/goodbye/index.html’ page?
You will need the Base64 encoding of this string:

/logout.html?return=L2dvb2RieWUvaW5kZXguaHRtbA==

Well, here’s your help, I found a nice online Base64 converter, which does this job for you.

Check out my website to see it working in a Joomla 1.5 page.

Using HTML entities is the right way to ensure all the characters on your page are validated.
Sometimes, it’s really irritating to Google for the correct encoded HTML Entity,
or scroll through a list of 250 HTML Entity mappings.

I found a really cool entity look-up tool which takes this pain away!

In software you don’t want all information user-readable in the POST or GET request. Therefore
you need to encrypt your info’s. This can be done by MD5 (Message-Digest algorithm 5).
A widely used, partially insecure cryptographic hash function with a 128-bit hash value. As an Internet standard (RFC 1321), MD5 has been employed in a wide variety of security applications, and is also commonly used to check the integrity of files. An MD5 hash is typically expressed as a 32 digit hexadecimal number.

For example:

MD5("Pa's wijze lynx bezag vroom het fikse aquaduct") = b06c0444f37249a0a8f748d3b823ef2a

I will post you a pseudo code for building MD5 formula’s, but of course there are already tools on the internet:
Online MD5 Encryptor
Online MD5 Encryptor

Pseudo code – MD5 hash:

//Note: All variables are unsigned 32 bits and wrap modulo 2^32 when calculating
var int[64] r, k

//r specifies the per-round shift amounts
r[ 0..15] := {7, 12, 17, 22,  7, 12, 17, 22,  7, 12, 17, 22,  7, 12, 17, 22}
r[16..31] := {5,  9, 14, 20,  5,  9, 14, 20,  5,  9, 14, 20,  5,  9, 14, 20}
r[32..47] := {4, 11, 16, 23,  4, 11, 16, 23,  4, 11, 16, 23,  4, 11, 16, 23}
r[48..63] := {6, 10, 15, 21,  6, 10, 15, 21,  6, 10, 15, 21,  6, 10, 15, 21}

//Use binary integer part of the sines of integers (Radians) as constants:
for i from 0 to 63
    k[i] := floor(abs(sin(i + 1)) × (2 pow 32))

//Initialize variables:
var int h0 := 0x01234567
var int h1 := 0x89ABCDEF
var int h2 := 0xFEDCBA98
var int h3 := 0x76543210

//Pre-processing:
append "1" bit to message
append "0" bits until message length in bits ≡ 448 (mod 512)
append bit /* bit, not byte */ length of unpadded message as 64-bit little-endian integer to message

//Process the message in successive 512-bit chunks:
for each 512-bit chunk of message
    break chunk into sixteen 32-bit little-endian words w[i], 0 ≤ i ≤ 15

    //Initialize hash value for this chunk:
    var int a := h0
    var int b := h1
    var int c := h2
    var int d := h3

    //Main loop:
    for i from 0 to 63
        if 0 ≤ i ≤ 15 then
            f := (b and c) or ((not b) and d)
            g := i
        else if 16 ≤ i ≤ 31
            f := (d and b) or ((not d) and c)
            g := (5×i + 1) mod 16
        else if 32 ≤ i ≤ 47
            f := b xor c xor d
            g := (3×i + 5) mod 16
        else if 48 ≤ i ≤ 63
            f := c xor (b or (not d))
            g := (7×i) mod 16

        temp := d
        d := c
        c := b
        b := b + leftrotate((a + f + k[i] + w[g]) , r[i])
        a := temp

    //Add this chunk's hash to result so far:
    h0 := h0 + a
    h1 := h1 + b
    h2 := h2 + c
    h3 := h3 + d

var int digest := h0 append h1 append h2 append h3 //(expressed as little-endian)