// preload images

if (document.images) {

button1 = new Image();
button1.src = "images/home_0.gif";
button1on = new Image();
button1on.src= "images/home_1.gif";

button2 = new Image();
button2.src = "images/overview_0.gif";
button2on = new Image();
button2on.src= "images/overview_1.gif";

button3 = new Image();
button3.src = "images/vlog_overview_0.gif";
button3on = new Image();
button3on.src= "images/vlog_overview_1.gif";

button4 = new Image();
button4.src = "images/vlog_2day_0.gif";
button4on = new Image();
button4on.src= "images/vlog_2day_1.gif";

button5 = new Image();
button5.src = "images/vlog_4day_0.gif";
button5on = new Image();
button5on.src= "images/vlog_4day_1.gif";

button6 = new Image();
button6.src = "images/vlog_adv_0.gif";
button6on = new Image();
button6on.src= "images/vlog_adv_1.gif";

button7 = new Image();
button7.src = "images/vlog_instruct_0.gif";
button7on = new Image();
button7on.src= "images/vlog_instruct_1.gif";

button8 = new Image();
button8.src = "images/vhdl_overview_0.gif";
button8on = new Image();
button8on.src= "images/vhdl_overview_1.gif";

button9 = new Image();
button9.src = "images/vhdl_2day_0.gif";
button9on = new Image();
button9on.src= "images/vhdl_2day_1.gif";

button10 = new Image();
button10.src = "images/vhdl_4day_0.gif";
button10on = new Image();
button10on.src= "images/vhdl_4day_1.gif";

button11 = new Image();
button11.src = "images/vlog_ver_0.gif";
button11on = new Image();
button11on.src= "images/vlog_ver_1.gif";

button12 = new Image();
button12.src = "images/vhdl_adv_0.gif";
button12on = new Image();
button12on.src= "images/vhdl_adv_1.gif";

button13 = new Image();
button13.src = "images/vhdl_instruct_0.gif";
button13on = new Image();
button13on.src= "images/vhdl_instruct_1.gif";

button14 = new Image();
button14.src = "images/rel_perladv_0.gif";
button14on = new Image();
button14on.src= "images/rel_perladv_1.gif";

button15 = new Image();
button15.src = "images/rel_perl_0.gif";
button15on = new Image();
button15on.src= "images/rel_perl_1.gif";

button16 = new Image();
button16.src = "images/rel_unix_0.gif";
button16on = new Image();
button16on.src= "images/rel_unix_1.gif";

button17 = new Image();
button17.src = "images/rel_linux_0.gif";
button17on = new Image();
button17on.src= "images/rel_linux_1.gif";

button18 = new Image();
button18.src = "images/rel_javascript_0.gif";
button18on = new Image();
button18on.src= "images/rel_javascript_1.gif";

button19 = new Image();
button19.src = "images/rel_instruct_0.gif";
button19on = new Image();
button19on.src= "images/rel_instruct_1.gif";

button20 = new Image();
button20.src = "images/public_0.gif";
button20on = new Image();
button20on.src= "images/public_1.gif";

button21 = new Image();
button21.src = "images/customized_0.gif";
button21on = new Image();
button21on.src= "images/customized_1.gif";

button22 = new Image();
button22.src = "images/emaillist_0.gif";
button22on = new Image();
button22on.src= "images/emaillist_1.gif";

button23 = new Image();
button23.src = "images/comments_0.gif";
button23on = new Image();
button23on.src= "images/comments_1.gif";

button24 = new Image();
button24.src = "images/ver_instruct_0.gif";
button24on = new Image();
button24on.src= "images/ver_instruct_1.gif";

button25 = new Image();
button25.src = "images/vlog_1day_0.gif";
button25on = new Image();
button25on.src= "images/vlog_1day_1.gif";

}

// that's it

function select(imgDocID,imgObjName) {

document.images[imgDocID].src = eval(imgObjName + ".src");

}