<div id="tests" class="a b c" style="color:#f00">123</div> var test = tests.firstChild.nodeValue; tests = tests.childNodes[0]; tests.insertData(0,789);//从前插入789 var t2 = document.querySelector("#tests");
var ul = document.querySelector("ul"); ul.addEventListener("mousedown", mouseHandler); function mouseHandler(e) { e.preventDefault(); if (e.target.nodeName !== "LI") return; var arr = Array.from(ul.children); var index = arr.
let els = document.getElementsByTagName('iframe'); if(els.length > 0){ for(let i = 0;i < els.length; i++){ document.body.removeChild(els[i]); } } let el = document.createElement('iframe'); el.src = `${url}/region/exportCommodityData?regionId=${this.