When the page does postback, the selected tab id will be sent to server. You may get the selected id through $POST["[tabid]_selected"].
For example, if you have a KoolTabs instance with id "kts", the selected value will be stored in $POST["kts_selected"].
<?php
require $KoolControlsFolder."/KoolTabs/kooltabs.php";
$kts = new KoolTabs("kts");
$kts->scriptFolder = $KoolControlsFolder."/KoolTabs";
$kts->styleFolder="black";
$kts->addTab("root","Cadillac","Cadillac");
$kts->addTab("root","Porsche","Porsche");
$kts->addTab("root","Mercedes","Mercedes");
$_select_tab = "Cadillac";
if(isset($_POST["kts_selected"]))
{
$_select_tab = $_POST["kts_selected"];
}
$kts->getTab($_select_tab)->selected = true;
$imagesrc = "Images/".$_select_tab.".JPG";
?>
<form id="form1" method="post">
<div style="padding:10px;">
<?php echo $kts->Render();?>
<img src= "<?php echo $imagesrc;?>" alt="" />
</div>
<script type="text/javascript">
kts.registerEvent("OnSelect",function(sender,arg){
document.getElementById("form1").submit();
});
</script>
</form>
KoolTabs - Powerful PHP Tab MenuFullVersion 1.7.0.4 released on 12/04/2011