function a(action){
var img_div = document.getElementById('a');
if(action == 1){
img_div.style.display = "block";
} else {
img_div.style.display = "none";
}
}
function b(action){
var img_div = document.getElementById('b');
if(action == 1){
img_div.style.display = "block";
} else {
img_div.style.display = "none";
}
}
function c(action){
var img_div = document.getElementById('c');
if(action == 1){
img_div.style.display = "block";
} else {
img_div.style.display = "none";
}
}
function d(action){
var img_div = document.getElementById('d');
if(action == 1){
img_div.style.display = "block";
} else {
img_div.style.display = "none";
}
}
function MM_goToURL() { //v3.0
  var i, args=MM_goToURL.arguments; document.MM_returnValue = false;
  for (i=0; i<(args.length-1); i+=2) eval(args[i]+".location='"+args[i+1]+"'");
}