<script>
let current_state_url =
""
;
let forward_stack = [];
let backward_stack = [];
function
visit_new_url(url)
{
if
(current_state_url !=
""
)
{
backward_stack.push(current_state_url);
}
current_state_url = url;
}
function
forward()
{
if
(forward_stack.length == 0 ||
current_state_url == forward_stack[forward_stack.length - 1])
{
document.write(
"Not Available"
+
"</br>"
);
return
;
}
else
{
backward_stack.push(current_state_url);
current_state_url = forward_stack[forward_stack.length - 1];
forward_stack.pop();
}
}
function
backward()
{
if
(backward_stack.length == 0 ||
current_state_url ==
backward_stack[backward_stack.length - 1])
{
document.write(
"Not Available"
+
"</br>"
);
return
;
}
else
{
forward_stack.push(current_state_url);
current_state_url = backward_stack[backward_stack.length - 1];
backward_stack.pop();
}
}
function
simulatorFunction()
{
let url =
"ajay.com"
;
visit_new_url(url);
document.write(
"Current URL is: "
+ current_state_url +
"</br>"
);
url =
"abc.com"
;
visit_new_url(url);
document.write(
"Current URL is: "
+ current_state_url +
"</br>"
);
backward();
document.write(
"Current URL after pressing"
+
" Backward button is: "
+
current_state_url +
" </br>"
);
forward();
document.write(
"Current URL after pressing"
+
" Forward button is: "
+
current_state_url +
" </br>"
);
url =
"nikhil.com"
;
visit_new_url(url);
document.write(
"Current URL is: "
+
current_state_url +
" </br>"
);
forward();
document.write(
"Current URL after pressing"
+
" Forward button is: "
+
current_state_url +
" </br>"
);
backward();
document.write(
"Current URL after pressing"
+
" Backward button is: "
+
current_state_url +
" </br>"
);
}
simulatorFunction();
</script>