Changing strings on the page

[admin]

if I set up an array of strings as follows:

strings=new Array(3);
strings[0]="This is string number 1";
strings[1]="String number 2 is here";
strings[2]="Here is string number 3";

I then want to display the first string. When you click a button I want to change this string to the second string another click will change it to the third string. How would I go about doing this without reloading, or disturbing any other content on the page?

thanks a lot