var IE4 = (document.all) ? true : false;
var NS4 = (document.layers) ? true : false;

function showb() {
  if(IE4) {
    alert("internet explorer ") ;
	}
  if(NS4) {
    alert(" netscape browser ") ;
	}
}

function doc_setVisibility(id, str) {
  if (NS4) {
    eval("document." + id).visibility = str;
  }
  else {
    eval("document.all." + id).style.visibility = str;
  }
}

function hideall() {
  doc_setVisibility("t1s","hidden");
  doc_setVisibility("t2s","hidden");
  doc_setVisibility("t3s","hidden");  
  doc_setVisibility("t4s","hidden");
  doc_setVisibility("t5s","hidden");
}

function show1() {
  doc_setVisibility("t1s","visible");
  doc_setVisibility("t2s","hidden");
  doc_setVisibility("t3s","hidden");  
  doc_setVisibility("t4s","hidden");
  doc_setVisibility("t5s","hidden");
}

function show2() {
  doc_setVisibility("t1s","hidden");
  doc_setVisibility("t2s","visible");  
  doc_setVisibility("t3s","hidden");
  doc_setVisibility("t4s","hidden");
  doc_setVisibility("t5s","hidden");
}

function show3() {
  doc_setVisibility("t1s","hidden");
  doc_setVisibility("t2s","hidden");
  doc_setVisibility("t3s","visible");  
  doc_setVisibility("t4s","hidden");
  doc_setVisibility("t5s","hidden");
}

function show4() {
  doc_setVisibility("t1s","hidden");
  doc_setVisibility("t2s","hidden");
  doc_setVisibility("t3s","hidden");  
  doc_setVisibility("t4s","visible");
  doc_setVisibility("t5s","hidden");
}

function show5() {
  doc_setVisibility("t1s","hidden");
  doc_setVisibility("t2s","hidden");
  doc_setVisibility("t3s","hidden");  
  doc_setVisibility("t4s","hidden");
  doc_setVisibility("t5s","visible");
}