jQuery学习（三）---jquery 与 DOM操作

来源：互联网发布：淘宝购物最便宜的软件编辑：程序博客网时间：2024/06/04 18:04

实例一：

  var title = p.attr("title");
  var title2 = li.attr("title");
  var text = li.text();

  alert(title);//hello world
  alert(title2);//1
  alert(text);//好
  */
  /*
  $("ul").append("<li title='abc'>hello</li>")
    .append("<li title='xyz'>world</li>");
  */
  $("<li title='abc'>hello</li>").appendTo("ul");
});
</script>
</head>

<body>
<p title="hello world">你觉得学校怎么样？</p>
<ul>
<li title="o">一般</li>
<li title="1">好</li>
<li title="2">很好</li>
<li title="3">非常好</li>
<li title="4">好得不得了</li>
<li title="5">好的无法形容</li>
</ul>
</body>
</html>

实例二：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>无标题文档</title>
<script type="text/javascript" src="jquery-1.8.1.js">
</script>
<script type="text/javascript">
/*
var addItems = function()
{

  document.getElementById("div1").innerHTML="";//避免重复点击
  var value = parseInt(document.getElementById("itemsNumber").value);
  //alert(value);
  for(var i = 0; i < value; i++)
  {
   var input = document.createElement("input");
   input.setAttribute("type","text");

</script>
</head>

实例三：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>无标题文档</title>
<script type="text/javascript" src="jquery-1.8.1.js">
</script>
<script type="text/javascript">
$(function(){
  var li1 = "<li title='hello'>hello1</li>";
  var li2 = "<li title='hello'>hello2</li>";
  var li3 = "<li title='hello'>hello3</li>";

  $("ul").append(li1);
  $("ul").prepend(li2);
  $("ul li:eq(4)").after(li3);
});
</script>
</head>

运行结果：

实例四：

实例五：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>无标题文档</title>
<script type="text/javascript" src="jquery-1.8.1.js">
</script>
<script type="text/javascript">
$(function(){
  //remove()方法返回被移除的节点的jQuery对象
  var removedLi = $("ul li:eq(3)").remove();
  removedLi.appendTo($("ul"));

$("ul li").remove("li[title = 2]");

$("ul li:eq(3)").empty();
});
</script>
</head>

运行结果：

实例六：动态文件添加和删除

  var br = document.createElement("br");
  var input = document.createElement("input");
  var btn = document.createElement("input");

  input.setAttribute("type","file");
  btn.setAttribute("type","button");
  btn.setAttribute("value","删除");

  btn.onclick = function(){
   div.removeChild(br);
   div.removeChild(input);
   div.removeChild(btn);
  }

  div.appendChild(br);
  div.appendChild(input);
  div.appendChild(btn);
}
*/
$(function(){
  $("#addFile").click(function(){
   var br = $("<br/>");
   var input = $("<input type='file'>");
   var btn = $("<input type='button' value='删除'>");
   $("#file").append(br).append(input).append(btn);
   btn.click(function(){
    br.remove();
    input.remove();
    btn.remove();
   });
  });
});
</script>
</head>

结果如下：

实例七：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>无标题文档</title>
<script type="text/javascript" src="jquery-1.8.1.js">
</script>
<script type="text/javascript">
$(function(){
  $("#username").focus(function(){
   var value = $(this).val();
   if(value == this.defaultValue)
   {
    $(this).val("");
   }
  });
  $("#username").blur(function(){
   var value = $(this).val();
   if(value == "")
   {
    $(this).val(this.defaultValue);
   }
  });
});
</script>
</head>