详解js的事件处理函数和动态创建html标记方法

window.onload = function() {
 script1;
 script2;
 script3;
 ......
 }

 function addLoadEvent(func)() {
 var oldonload = window.onload;
 if (typeof window.onload !="function") {
  window.onload = func;
 } else {
  window.onload = function() {
   oldonload();
   func;
  }
 }
 }

<!DOCTYPE html>
 <html>
 <head>
 <meta chaset="utf-8" />
 <title>document.write</title>
 <body>
  <script>
  <!--可以很方便的插入元素标签,尤其是字符串.但是它与网页设计应将行为(脚本)和结构(html标签)分离的原则-->
  document.write("<p>This is inserted by document.write</p>");
  </script>
 </body>
 </head>
 </html>

<div id="testdiv">
 </div>
 window.onload = function() {
 var testdiv = document.getElementById("testdiv");
 testdiv.innerHTML = "<p>This is inserted by <em>innerHTML</em></p><en>";
 }

 window.onload = function() {
  var testdiv = document.getElementById("testdiv");
  var para = document.createElement("p");
  testdiv.appendChild(para);
  var context1 = doument.createTextNode("This is inserted by ");
  para.appendChild(context1);
  var emphasis = document.createElement("em");
  para.appendChild(emphasis);
  var context2 = document.createTextNode("method of domcore");
  emphasis.appendChild(context2);
 }

function insertAfter(newElement, targetElement) {
 var parent = targetElement.parentNode;
 if (parent.lastChild == targetElement) {
  parent.appendChild(newElement);
 } else {
  targetElement.inserBefore(newElement, targetElement.nextSibling);
 }
}