function da_leist(){
 if(document.getElementById)
     document.getElementById("leist-t").style.visibility="visible";
     document.getElementById("prod-t").style.visibility="hidden";
   }

function ex_leist(){
 if(document.getElementById)
     document.getElementById("leist-t").style.visibility="hidden";
     document.getElementById("prod-t").style.visibility="hidden";
   }

function da_prod(){
 if(document.getElementById)
     document.getElementById("prod-t").style.visibility="visible";
     document.getElementById("leist-t").style.visibility="hidden";
     
   }

function ex_prod(){
 if(document.getElementById)
     document.getElementById("prod-t").style.visibility="hidden";
     document.getElementById("leist-t").style.visibility="hidden";
   }