Uncaught Typeerror: Object is not a Function. Clone html and Back button

Question

I’m having a system problem where I need to make a button for come back and thought of a function to clone using and a function for the button come back.

But the problem is that when I log in to the system I go to a menu and when I click on an option it loads a sub-menu in it grid , is where all user interaction occurs, when I click on the back it performs the function back go back to the menu, but if I try to access another module the functions do not work and return this error:

Uncaught Typeerror: Object is not a Function.

Code:

var n= 0;
var divClone=[""] ;  

function clone(){
    divClone[n]=$("#grid").clone();
    n++ 
}

function back(){
    n--;
    $(''#grid'').html(divClone[n]);
}