Answer 1

No probs, You made a simple mistake on line 18 it should be (noo==false)

When you click on the element it should toggle between both statements 👍

Answer 2

Hi please attach your code to your question using +insert tab

Answer 3

hi Gautam Yadav
I would change your javascript to:
the black nav area disappear or not. Do you want this?
<script>
var noo=true;
function togglenav(){
if(noo){ document.getElementById("no").style.left="-100px"
noo=false;
} else {
document.getElementById("no").style.left="0px"
noo=true;
}
}
</script>

for more information or further possible solution for this see
https://www.w3schools.com/howto/howto_js_toggle_hide_show.asp
or with toggle style class
https://www.w3schools.com/howto/tryit.asp?filename=tryhow_js_toggle_class