<body>
<ul><ul/> <div><div>
</body>
1. Internal added plus to the relationship between father and son
was added back to prepend append prepend
let li = $ ( "<li > I add an internal </ li>") $ ( "ul") the append (li).;
2. External Add to add the phrase are brothers
let div = $ ( "<div > I add external </ div>") $ ( "div") the before (div).;
3. Removing elements
$ ( "ul"). the Remove () // directly delete this element $ ( "ul"). empty () // delete this element inside the child nodes $ ( "ul"). HTML () // this with empty the same effect