<script type="text/javascript">
var answerFunction;
function myConfirm(text,button1,button2,answerFunc) {
   var box=document.getElementById("confirmBox");
   box.getElementsByTagName("p")[0].firstChild.nodeValue=text;
   var button=box.getElementsByTagName("input");
   button[0].value=button1;
   button[1].value=button2;
   answerfunction=answerFunc;
   box.style.visibility="visible";
} 
function answer(response) {
   document.getElementById("confirmBox").style.visibility="hidden";
   answerFunction(response);
} 
function tester(button) {
   myConfirm("Wirklich Archivieren?<br/>Dies dient dem Löschen des Kontraktes!!!","OK","Abbrechen",
      function(answer) {
         var field=getElementsById("archive");
         if (answer)
            field.value="JA";
         else
            field.value="NEIN";
      }
   );
}
</script>

<div id="confirmBox"><p>.....</p></div>

<input type="submit" ..... onsubmit="tester(this)"/>