页面 Loading 条基本人人都会用。它的原理很简单:在页头放置一个文字或者图片的 loading 状态,然后页尾载入一段 JS 隐藏掉,即根据浏览器的载入顺序来实现的简易 Loading 状态条。
上图展示了传统 Wordpress 模板在浏览器中的载入顺序,Loading 条的出现和消失分布于头尾。
如果我们在页面的不同位置放置多个 JS ,每个 JS 用于逐步增加 Loading 条的宽度,那么这个 Loading 条无疑会更具实用价值。它在一定程度上缓解了访客等待载入的枯燥感,同时还能客观反映页面载入的进度。若再配以 jQuery 内建的动画效果,其完全可以与浏览器自带的状态条媲美。
先来看一个演示:地址 。
要得到演示上的进度条效果,首先 ,引入 jQuery 框架(一定要放在页头 <head>
标签内)。然后在 <body> 标签起始位置放置:
<div id="loading"><div></div></div>
CSS 可以这么写:
#loading {
width:100px;
height:20px;
background:#A0DB0E;
padding:5px;
position:fixed;
left:0;
top:0;
}
#loading div {
width:1px;
height:20px;
background:#F1FF4D;
}
准备工作到这里就做好了。
接着 ,请随意发挥,依照你对图二的理解,在模板各个部分的适当位置放置:
<script type="text/javascript">
$("#loading div").animate({width:"16px "})
</script>
其中红色数值应该随载入顺序逐步增加,直到 footer.php。另外别忘了在 footer.php 最末尾放上:
<script type="text/javascript">
$("#loading").fadeOut()
</script>
用于载入完毕后隐藏进度条。
第二种
- <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
- <html xmlns="http://www.w3.org/1999/xhtml">
- <head>
- <title>Loading Status Bar</title>
- <meta name="robots" content="noindex,follow" />
- <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.2.6/jquery.min.js"></script>
- <script type="text/javascript">
- document.writeln("<style type=\"text\/css\">#loading{width:100px;height:20px;background:#A0DB0E;padding:5px;position:fixed;left:0;top:0}#loading div{width:1px;height:20px;background:#F1FF4D;font:10px/20px Arial}<\/style>");
- </script>
- <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /></head>
- <body>
- <noscript>您的浏览器不支持 Javascript</noscript>
- <div id="loading">
- <div></div>
- </div>
- <? for($i=0;$i<100000;$i++){ echo $i;} ?>
- <script type="text/javascript">$("#loading div").animate({width:"16px"}).text("16%")</script>
- <? echo '<br><br><br>'; for($i=0;$i<100000;$i++){ echo $i;} ?>
- <script type="text/javascript">setTimeout(function(){$("#loading div").animate({width:"34px"}).text("34%")},500)</script>
- <script type="text/javascript">setTimeout(function(){$("#loading div").animate({width:"67px"}).text("67%")},1000)</script>
- <script type="text/javascript">setTimeout(function(){$("#loading div").animate({width:"82px"}).text("82%")},1500)</script>
- <script type="text/javascript">setTimeout(function(){$("#loading div").animate({width:"100px"}).text("100%")},2000)</script>
- <script type="text/javascript">setTimeout(function(){$("#loading").hide(500)},3000)</script>
- </body>
- </html>
第三种 导向型
- <!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=UTF-8">
- <title>Loading</title>
- <style type="text/css">
- .proccess{
- border:1px solid;
- width:8px;
- height:8px;
- background:#ffffff;
- margin:3px;
- }
- </style>
- <script language="JavaScript">
- var url = 'http://deographics.com/';
- </script>
- </head>
- <body onLoad="location.href = url;" style='overflow:hidden; overflow-y:hidden'>
- <div align=center>
- <font class=fontbig>友情提示,页面正在加载中,请等待......</font>
- <div align="center">
- <form method="post" name="proccess">
- <script type="text/javascript">
- for(i=0;i<30;i++){
- document.write("<input class=proccess>");
- }
- </script>
- </form>
- </div>
- <div align="center">
- <script language=JavaScript>
- var p=0,j=0;
- var c=new Array('lightskyblue','white')
- setInterval('proccess();',100)
- function proccess(){
- document.forms.proccess.elements[p].style.background=c[j]; p+=1;
- if(p==30){ p=0;j=1-j; }
- }
- </script>
- </div>
- </div>
- <div align="center">
- <script>
- if (document.layers){
- document.write('<Layer src="' + url + ' " visibility="hide"> </Layer>');
- }else if (document.all || document.getElementById){
- document.write('<iframe src="' + url + '" style="visibility: hidden;"></iframe>');
- }else{
- location.href = url;
- }
- </script>
- </div>
- </body>
- </html>
- <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
- <html xmlns="http://www.w3.org/1999/xhtml">
- <head>
- <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
- <title>Iframe Loading</title>
- </head>
- <body>
- <div id="load"><img src="http://sysimages.tq.cn/images/analysis_images/ajax-loader.gif" /> loading...</div>
- <iframe style="visibility:hidden" onreadystatechange="stateChangeIE(this)" onload="stateChangeFirefox(this)" name="callframe" id="callframe" width="420" height="100" frameborder="0" scrolling="no" marginheight="0"></iframe>
- <script>
- function stateChangeIE(_frame){
- if (_frame.readyState=="interactive"){ //state: loading ,interactive, complete
- var loader = document.getElementById("load");
- loader.innerHTML = "";
- loader.style.display = "none";
- _frame.style.visibility = "visible";
- }
- }
- function stateChangeFirefox(_frame){
- var loader = document.getElementById("load");
- loader.innerHTML = "";
- loader.style.display = "none";
- _frame.style.visibility = "visible";
- }
- callframe.location.href="http://deographics.com/";
- </script>
- </body>
- </html>
1: (Loading) the send( ) method has been invoked, request in progress.
2: (Loaded) the send( ) method has completed, entire response received.
3: (Interactive) the response is being parsed.
4: (Completed) the response has been parsed, is ready for harvesting.
0 - (未初始化)还没有调用send()方法
1 - (载入)已调用send()方法,正在发送请求
2 - (载入完成)send()方法执行完成,已经接收到全部响应内容
3 - (交互)正在解析响应内容
4 - (完成)响应内容解析完成,可以在客户端调用了
- <html>
- <head>
- <title>JavaScript图片预加载代码,显示loading</title>
- <style type="text/css">
- div{
- border:#aaaaaa 3px solid;
- width:200px;
- padding:2px;
- margin:2px 9px;
- font-size:12px;
- line-height:22px;
- color:#999999;
- }
- .ipt1{
- width:160px;
- font-size:12px;
- color:#1F6478;
- border:#999999 1px solid;
- margin-left:9px;
- }
- .ipt2{
- border:#999999 1px solid;
- margin-left:6px;color:#666666;
- }
- p{
- margin:0px;
- padding:0px;
- background-image:url(http://www.codefans.net/jscss/demoimg/loading.gif);
- background-position:center;
- background-repeat:no-repeat;
- width:200px;
- height:200px;
- text-align:center;
- font-size:12px;
- color:#999999;
- line-height:26px;
- }
- </style>
- <script language="javascript" type="text/javascript">
- function preloadimg(url,obj,ipt){
- var img = new Image();
- obj.innerHTML = "<p>Loading...</p>";
- img.onload = function(){
- obj.innerHTML = "";
- obj.style.width = String(img.width)+"px";
- ipt.style.width = String(img.width-40)+"px";
- obj.appendChild(img);
- };
- img.onerror = function(){
- obj.innerHTML="Loading Fail !"
- };
- img.src = url; //img.src 一定要写在img.onload之后,否则在IE中会出现问题
- }
- function show(){
- var div = document.getElementsByTagName("div")[0];
- var input = document.getElementsByTagName("input");
- preloadimg("http://www.codefans.net/jscss/demoimg/wall9.jpg",div,input[0]);
- input[0].onclick = function(){this.value=""};
- input[1].onclick = function(){preloadimg(input[0].value,div,input[0]);}
- }
- window.onload = show;
- </script>
- </head>
- <body>
- <div></div><br />
- <input type="text" value="将图片地址粘贴在这里" class="ipt1"/><input type="button" value="开始加载" class="ipt2"/>
- </body>
- </html>
- <script src="jquery-1.3.2.min.js" type="text/javascript"></script>
- <script src="MinmyLazyload.js" type="text/javascript"></script>
- <body>
- <img original="http://justcoding.iteye.com/uploadfiles/20100424-2_20914.jpg">
- <img original="http://justcoding.iteye.com/uploadfiles/20100423-1_85399.jpg">
- <script type="text/javascript">$("img").lazyload({ placeholder: "img-loader.gif", effect:"fadeIn" });
- </script>
- </body>
- <style>
- #loading{font-size:12px;color:#FFFFFF;background:#FF0000;position:absolute;top:500px;left:500px; z-index:1002; padding:2px 10px 2px 10px}
- </style>
- <body>
- <div id="loading">页面加载中…</div>
- ..........
- <script type="text/javascript">
- document.write('<style>#loading{display:none;}</style>');
- </script>
- </body>
- </html>