onMouseUp
The instruction(s) to be executed are placed within quotes. This event handler will execute the instruction(s) when a button on the mouse has been pressed and released.

The following example will display a text message of your choosing in a message box when the mouse button is released over the 'image.jpg' graphic:
<IMG SRC="image.jpg" onMouseUp="msgWindow.document.write('-- Insert text message here --')"
This Event Handler is used with the following:

A
ACRONYM
ADDRESS
APPLET
AREA
B
BIG
BLOCKQUOTE
BODY
BUTTON
CAPTION
CENTER
CITE
CODE
DD
DEL
DFN
DIR
DIV
DL
DT
EM
FIELDSET
FONT
FORM
H1
H2
H3
H4
H5
H6
HR
I
IMG
INS
KBD
LABEL
LEGEND
LI
LISTING
MAP
MARQUEE
MENU
P
PLAINTEXT
PRE
Q
S
SAMP
SELECT
SMALL
SPAN
STRIKE
STRONG
SUB
SUP
TABLE
TBODY
TD
TEXTAREA
TFOOT
TH
THEAD
TR
TT
U
UL
VAR
XMP