Javascript/node.textContent

//　テキスト内容の取得
var s1Div01 = document.getElementById("s1Div01").textContent;
console.log(s1Div01);
// テキストの内容を設定
document.getElementById("s1Div02").textContent = "s1Div02";
	

//文字列を一文字ずつspanで囲む
var textbox = document.querySelector('#s2Div');
var text = textbox.textContent;
textbox.innerHTML = null;
text.split('').forEach(function (c) {
  textbox.innerHTML += 'span>' + c + '/span>';
});