四时宝库

let str = 'haaa'
console.log(str.match(/ha+?/));//['ha'  +?禁止匹配多个
console.log(str.match(/ha*?/));//['h',   *?倾向于0个
console.log(str.match(/ha{1,10}?/))//['ha'  向小的方向匹配
console.log(str.match(/ha{1,}?/))//['ha'  向小的方向匹配
console.log(str.match(/ha?/))//['ha'  ?本身就是0或者1个
console.log(str.match(/ha??/))//['h'  ??就是0个

需求：span变h4 描红 内容前面加上 佳佳

<div>
    <span>jiasdgs.com</span>
    <span>jisdfsajia.cn</span>
    <span>jiasgasjia.otg</span>
  </div>

let divContent = document.querySelector('div');
let reg = /<span>([\s\S]+?)<\/span>/gi;
  divContent.innerHTML = divContent.innerHTML.replace(reg,(v,p1)=>{
  console.log(v,p1);
  return `<h4 style="color:red">佳佳${p1}<\/h4>`
})