Dynamically changing the button

Hi,
My requirement is to have a button with an initial and onclick it should change to a button with another initial.these button will be taken from a database.
How can i do this??...i am using ASP ....

 

i mean button initial will be taken from the database

 

Example:

HTML:

<img src="a.gif" onClick="this.src='b.gif';"> <!-- For an image -->
<input type="button" value="Click Me" onClick="this.value='Clicked';">