To show the page URL names on the buttons:
<form method="get" action="<this page's address>">
<input type="submit" name="page" value="page1" />
<input type="submit" name="page" value="page2" />
</form>
Or, to show other text there:
<form method="get" action="<this page's address>">
<input type="submit" name="page" value="Page 1 button text" onclick="this.value='page1'" />
<input type="submit" name="page" value="Page 2 button text" onclick="this.value='page2'" />
</form>
Or lastly, with a hidden field & jQuery:
<form method="get" action="<this page's address>">
<input type="submit" value="Page 1 button text" onclick="$('#hidden').val('page1')" />
<input type="submit" value="Page 2 button text" onclick="$('#hidden').val('page2')" />
<input type="hidden" name="page" id="hidden" />
</form>