<!-- Code for Main Window link -->
<a href="#" onclick="tb_open_new('window_one.html?TB_iframe=true&height=400&width=400&modal=true')">Open Thickbox without href attribute</a>

<!-- Code of Window One buttons-->
<input type="button" value="Close & Open - Window Two" onclick="self.parent.tb_open_new('window_two.html?TB_iframe=true&height=400&width=500&modal=true')" />
<input type="button" value="Close" onclick="self.parent.tb_remove();" />

<!-- Code of Window Two buttons -->
<input type="button" value="Close & Open - Window One" onclick="self.parent.tb_open_new('window_one.html?TB_iframe=true&height=400&width=400&modal=true')" />
<input type="button" value="Close & Call Parent/Main Window function" onclick="self.parent.tb_remove('show_code();');" />