Example of the meaning of that in javascript

You may find that the code written by someone else has the following sentence: var that = this;. What does this mean?

In javascript, this indicates the current object.

Var that = this is to copy the current this object to that variable. What is the significance of doing so?

Copy codeThe Code is as follows:
$ ('# Zhetenga'). click (function (){
// This is clicked # zhetenga
Var that = this;
$ ('. Zhetenga'). each (function (){
// This is the current object in the. zhetenga loop.
// That is still the one you just clicked # zhetenga
});
});

As you can see, this object will change at any time in the program, and after var that = this, that will still point to the current this before it is changed, so that the original object will not be found.