innerHTML 和 innerText

 window.onload = function () {
      //用appendChild()
       var oImg = document.createElement("img");
       oImg.className = "pic";
       oImg.src = "./images/bg-1.png";
       oImg.style.border = "solid green 2px";
       document.body.appendChild(oImg); 

      //如果用innerHTML来实现
      document.body.innerHTML = "<img class=‘pic‘ src=‘./images/bg-1.png‘ style=‘border:2px solid green‘/>";
    }

  window.onload = function () {
      var oP = document.getElementById("content");
      document.getElementById("txt1").value = oP.innerHTML;
      document.getElementById("txt2").value = oP.innerText;
    }

  <p id="content"><strong style="color:pink;">网站</strong></p>
  innerHTML是:<input id="txt1" type="text" /><br />
  innerText是:<input id="txt2" type="text" />

  window.onload = function () {
      var oDiv = document.getElementsByTagName("div")[0];
      oDiv.innerHTML = "<span>绿叶学习网</span>                    <span style=‘color:pink;‘>JavaScript</span>                    <span style=‘color:green;‘>入门教程</span>";
    }

  <div></div>