JavaScript插入节点

 document.write("<p>This is inserted.</p>");

window.onload = function() {
  var testdiv = document.getElementById("testdiv");
  testdiv.innerHTML="<p>I inserted <em>this</em> content.</p>";
}

window.onload = function() {
  var para = document.createElement("p");
  var txt1 = document.createTextNode("I inserted ");
  var emphasis = document.createElement("em");
  var txt2 = document.createTextNode("this");
  var txt3 = document.createTextNode(" content.");
  para.appendChild(txt1);
  emphasis.appendChild(txt2);
  para.appendChild(emphasis);
  para.appendChild(txt3);
  var testdiv = document.getElementById("testdiv");
  testdiv.appendChild(para);
}