无法从.range.value获取值

var input = document.getElementById("myInput");
var value = input.value;

var div = document.getElementById("myDiv");
var text = div.innerText;

var range = document.createRange();
range.selectNodeContents(document.getElementById("myDiv"));
var text = range.text;

var range = document.createRange();
range.selectNodeContents(document.getElementById("myDiv"));
var html = range.innerHTML;