The stack resolution in JavaScript, which has a relationship with delete.

1, the data in the stack is not deleted arbitrarily.

2, the data in the heap can be deleted arbitrarily.

Note : variables defined with eval ("var a") are stored in the stack.

The Var and function statements have a high priority in JavaScript and need to be pre-executed.

Pre-execution is because you need to calculate the size of the space occupied by local variable pointers in the scope to allocate memory to them.

Things in the stack cannot be deleted at will, so we cannot delete them.

But in some cases variables can also be placed in the heap, such as using Eval to execute the VAR statement to dynamically define variables during the run.

Because the computation of the stack space is calculated before the scope is run, variables that are dynamically defined during the run cannot be inserted into the stack, so they are temporarily allocated to the heap.

Since it is in the heap, we can delete it arbitrarily so that it does not contaminate the other scopes.

The stack resolution in JavaScript, which has a relationship with delete.