如何从html元素串中获取子串？

// 假设HTML元素串为<div id="myDiv">Hello World</div>
var htmlString = '<div id="myDiv">Hello World</div>';
var divElement = document.createElement('div');
divElement.innerHTML = htmlString;
var targetElement = divElement.querySelector('#myDiv');
var subString = targetElement.innerHTML;
console.log(subString); // 输出：Hello World

// 假设HTML元素串为<div id="myDiv">Hello World</div>
var htmlString = '<div id="myDiv">Hello World</div>';
var pattern = /<div id="myDiv">(.*?)<\/div>/;
var match = htmlString.match(pattern);
var subString = match[1];
console.log(subString); // 输出：Hello World