先上方法

	// 根据正则在字符串中查找结果
	function getData (inStr, inPattern,inList = []){
	  let reg = inPattern
	  let res = inStr.match(reg);
	  // 匹配不到东西了
	  if(res == null) return;
	  // 匹配到的那个结果
	  let matchStr = res[0];
	  // 匹配位置
	  let matchIndex = inStr.indexOf(matchStr)
	  if(res){
	    inList.push(res[0])
	    if((res[0].length + matchIndex) < inStr.length){
	      let newStr = inStr.slice(res[0].length + matchIndex)
	      getData(newStr,inPattern,inList)
	    } 
	  }
	  return inList;
	}

测试一下

	let str = '<p>这是一段文字</p><p><video src="http://tanda.zxyun119.com/admin/file/full/download/GQm0rxUJry/mp4" controls="controls" style="max-width:100%"></video></p><p>这是第二段文字</p><p><video src="http://tanda.zxyun119.com/admin/file/full/download/WZAp2DfEaM/mp4" controls="controls" style="max-width:100%"></video></p><p>这是第三段文本</p><p><iframe src="http://mpvideo.qpic.cn/0bf2zahsaaapx4ags2u5pfpv7sgdedea6iaa.f10002.mp4?dis_k=5c4cfea958eb9dbd786cd941bd0e8a4c&amp;dis_t=1636358558&amp;vid=wxv_1574211423902187523&amp;format_id=10002&amp;support_redirect=0&amp;mmversion=false"></iframe></p>', 
		reg = /<video.*?>.*?<\/video>|<iframe.*?>.*?<\/iframe>/;
		
	let list = genData(str, reg)
	/**
		[
		  '<video src="http://tanda.zxyun119.com/admin/file/full/download/GQm0rxUJry/mp4" controls="controls" style="max-width:100%"></video>',
		  '<video src="http://tanda.zxyun119.com/admin/file/full/download/WZAp2DfEaM/mp4" controls="controls" style="max-width:100%"></video>',
		  '<iframe src="http://mpvideo.qpic.cn/0bf2zahsaaapx4ags2u5pfpv7sgdedea6iaa.f10002.mp4?dis_k=5c4cfea958eb9dbd786cd941bd0e8a4c&amp;dis_t=1636358558&amp;vid=wxv_1574211423902187523&amp;format_id=10002&amp;support_redirect=0&amp;mmversion=false"></iframe>'
		]
	*/