This clock is a Java demo provided by Sun Microsystems. 
It is free to download from their web site.

If you don't see a clock, then your computer is not Java enabled.

Here is the HTML code for the portion of the page above.  The portion within the <applet> tags is in green:

<p><font face="Arial">This clock is a Java demo provided by Sun Microsystems.&nbsp;<br>It is free to download from their web site.</font></p>
<applet codebase="classes" code="JavaClock.class"
width="150" height="150" >
<param name="bgcolor" value="FFFFFF">
<param name="border" value="10">
<param name="ccolor" value="EEEEEE">
<param name="cfont" value="Arial|BOLD|18">
<param name="delay" value="100">
<param name="hhcolor" value="0000FF">
<param name="link" value="http://java.sun.com/openstudio/applets/clock.html">
<param name="mhcolor" value="00AA00">
<param name="ncolor" value="000000">
<param name="nradius" value="80">
<param name="shcolor" value="FF9999">
</applet>

<applet declares that the code following is for a Java applet.  codebase= gives the name of the subfolder that where 'class' file(s) are located.  If there is no codebase statement, then the class file(s) must be in the same folder as the HTML file that call it.  In this example, classes is the name of the sub folder.  code= gives the name of a Java code file to look for.  The Java code file is JavaClock.class

IMPORTANT:  In Java, file names are case sensitive.  If code="Javaclock.class" was used, but the file was named JavaClock.class, the applet would not work!

The remaining part of the code above is the part that you can change.  Below is a list of what each parameter line does.  Java uses hexadecimal colors by default.

bgcolor Background color of the applet in RGB hexadecimal
border Surrounding clock border, in pixels
ccolor Color of the clock in RGB hexadecimal
cfont A "|" delimited string that represents the name, type (PLAIN, BOLD, ITALIC),
and the point size of the clock number font.
delay Delay between frames in milliseconds
hhcolor Color of the hour hand in RGB hexadecimal
link URL to load if the applet is clicked
mhcolor Color of the minute hand in RGB hexadecimal
ncolor Color of the numbers in RGB hexadecimal
nradius Radius in pixels at which to draw the clock numbers
shcolor Color of the second hand in RGB hexadecimal

Clicking on the clock will take you to the Sun Microsystems web page where the clock download is located.  The download contains 4 applets - the clock is just one of them.  You can download the clock applet only by going to this page at JavaBoutique.  The download will include an HTML file.  Copy the code of the HTML file and paste it into the proper location within your web page's HTML.