Appendchild in document. createdocumentfragment under Javascript

When reading the shopping cart process analysis todayCode: Anchorfragment. appendchild (theachr );

Where: anchorfragment = Document. createdocumentfragment (); theachr = Dom. Get ('...');

According to the online operation, a piece of code is to be removed, but this is a bit difficult to understand here. It seems that it is required to be added to anchorfragment. It seems that there is no difference in removing a piece of code! I tested it myself to find out the cause and found that it meant to remove the code.

Later, I tried to check whether other elements are acceptable. The Code is as follows:

VaR DIV = Document. createelement ('div ');

Div. appendchild (DOM. Get ('A _ todo '));

I found that the results were the same. It seems that I have mistakenly understood the use of appendchild!