• Javascript 第七章


    <html>
     <head>
         <meta charset=utf-8>   
         <title></title>
     </head>
     <body>
     <h1>Snapshots</h1>
     <ul id="imageGallery">
         <li><a href="images/1 (1).png" title="picture1" alt="picture1">picture1</a></li>
         <li><a href="images/1 (2).png" title="picture2" alt="picture2">picture2</a></li>
         <li><a href="images/1 (3).png" title="picture3" alt="picture3">picture3</a></li>
     </ul>
     
    
     
     
     <script>
    
     function addLoadEvent(func){
            var oldonload = window.onload;
            if (typeof oldonload != 'function') {
                window.onload = func;
            }else{
                window.onload = function(){
                    oldonload();
                    func();
                }
            }
        }
    
    
     function prepareGallery(){    
         if (!document.getElementsByTagName || !document.getElementById) return false;    
         links = document.getElementsByTagName("a");
         for (var i = 0,j = links.length;i<j; i++) {
             links[i].onclick = function(){
                 return !showPic(this);
             }
         }
     }
     
         function showPic(whichPic){
             if (!document.getElementById("placeHolder")) return false;
             var source = whichPic.getAttribute("href");
             var placeholder = document.getElementById("placeHolder");
             if (placeholder.nodeName != "IMG") return false;
             placeholder.setAttribute("src",source);
     
             if (document.getElementById("description")) {
                 var text = whichPic.getAttribute("title");
                 var description = document.getElementById("description");
                 if (description.firstChild.nodeType == 3) {
                     description.firstChild.nodeValue = text;
                 }
         }
    
         return true;
         }
    
    
    
    function insertAfter(newElement,targetElement){
        var parent = targetElement.parentNode;
        if(parent.lastChild == targetElement){
            parent.appendChild(newElement);
        }else{
            parent.insertBefore(newElement,targetElement.nextSibling);
        }
    }
    
    
    
    function preparePlaceholder(){
        if(!document.createElement) return false;
        if(!document.createTextNode) return false;
        if(!document.getElementById) return false;
        if(!document.getElementById("imageGallery")) return false;
        var placeholder = document.createElement("img");
        placeholder.setAttribute("id","placeHolder");
        placeholder.setAttribute("src","images/pic0.jpg");
        placeholder.setAttribute("alt","my image gallery");
        var description = document.createElement("p");
        description.setAttribute("id","description");
        var h1 = document.createElement("h2");
        var text = document.createTextNode("Choose an image:");
        h1.appendChild(text);
        description.appendChild(h1);
        var gallery = document.getElementById("imageGallery");
        insertAfter(description,gallery);
        insertAfter(placeholder,description);
    
    }
    
    
         addLoadEvent(preparePlaceholder);
         addLoadEvent(prepareGallery);
    
    
     </script>
    
    
    <script>
    
    var request;
    
    function getHttpObject(){
        if(window.ActiveXObject){
            return new ActiveXObject("Microsoft.XMLHTTP");
        }
        else if (window.XMLHttpRequest) {
            return new XMLHttpRequest();
        }
    }
    
    function getNewContent(){
        request = getHttpObject();
        if (request) {
            request.onreadystatechange = handleStateChange;
            request.open("GET","file.py",true);
            request.send(null);
        }
    }
    /*
        0:请求未初始化(还没有调用 open())。
        1:请求已经建立,但是还没有发送(还没有调用 send())。
        2:请求已发送,正在处理中(通常现在可以从响应中获取内容头)。
        3:请求在处理中;通常响应中已有部分数据可用了,但是服务器还没有完成响应的生成。
        4:响应已完成;您可以获取并使用服务器的响应了。
    */
    function handleStateChange(){
        if (request.readyState == 4) {
            if (request.status == 200 || request.status == 0) {
                var placeholder = document.getElementById("placeHolder");
                var para = document.createElement("p");
                var text = document.createTextNode(request.responseText);
                para.appendChild(text);
                insertAfter(para,placeholder);
            }else{
                alert("unexpected error occurred.");
            }
        }
        
    }
    
    addLoadEvent(getNewContent);
    </script>
     </body>
     
     </html>

     

  • 相关阅读:
    关于互联网下的大数据及大数据对人的影响
    综合练习:词频统计=
    五星红旗
    页面性能
    前端一些常见的基础知识
    h5常见问题汇总及解决方案
    CF 184
    2013520 训练赛后总结
    斜率优化动态规划
    2013522 完美世界复赛第三场
  • 原文地址:https://www.cnblogs.com/mguo/p/2955435.html
Copyright © 2020-2023  润新知