JavaScript HTML DOMに新たな要素と削除要素を作成します.

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var para = document.createElement('p');//     p
var text = document.createTextMode('      ');//        
para.appendChid(text);//           P   
var para-2 = document.getElentById('dd');
para-2.appendChild(para);//    p      div 

var element = document.getElementById('dd');
var child = document.getElementById('p1');
element.removeChild(child);

var child = document.getElementById('p1');
child.parentNode.removeChild(child);