本文实例讲述了JS基于Ajax实现的网页Loading效果代码。分享给大家供大家参考，具体如下：
这是一款很不错的网页Loading效果，常用于Ajax交互式网页设计中，点击按钮即可弹出Loading框，若Loading框未加载完成时关闭网页，会弹出确认提示框，用于一些对安全性能要求高的网页交互处理中，比如付款操作。
运行效果截图如下：
在线演示地址如下：
http://demo.maopiaopiao.com/js/2015/js-ajax-web-loading-style-codes/
具体代码如下：
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>很不错的网页Ajax Loading效果</title>
</head>
<BODY STYLE="FONT-SIZE: 10pt; FONT-FAMILY: Verdana, Arial, Helvetica">
<SCRIPT LANGUAGE="JScript">
var NUMBER_OF_REPETITIONS = 40;
var nRepetitions = 0;
var g_oTimer = null;
function startLongProcess()
{
divProgressDialog.style.display = "";
resizeModal();
btnCancel.focus();
window.onresize = resizeModal;
window.onbeforeunload = showWarning;
continueLongProcess();
}
function updateProgress(nNewPercent)
{
divProgressInner.style.width = (parseInt(divProgressOuter.style.width)
* nNewPercent / 100)+ "px";
}
function stopLongProcess()
{
if (g_oTimer != null)
{
window.clearTimeout(g_oTimer);
g_oTimer = null;
}
// Hide the fake modal DIV
divModal.style.width = "0px";
divModal.style.height = "0px";
divProgressDialog.style.display = "none";
// Remove our event handlers
window.onresize = null;
window.onbeforeunload = null;
nRepetitions = 0;
}
function continueLongProcess()
{
if (nRepetitions < NUMBER_OF_REPETITIONS)
{
var nTimeoutLength = Math.random() * 250;
updateProgress(100 * nRepetitions / NUMBER_OF_REPETITIONS);
g_oTimer = window.setTimeout("continueLongProcess();", nTimeoutLength);
nRepetitions++;
}
else
{
stopLongProcess();
}
}
function showWarning()
{
return "Navigating to a different page or refreshing the window could cause you to lose precious data.nnAre you*absolutely* certain you want to do this?";
}
function resizeModal()
{
divModal.style.width = document.body.scrollWidth;
divModal.style.height = document.body.scrollHeight;
divProgressDialog.style.left = ((document.body.offsetWidth -
divProgressDialog.offsetWidth) / 2);
divProgressDialog.style.top = ((document.body.offsetHeight -
divProgressDialog.offsetHeight) / 2);
}
</SCRIPT>
<INPUT TYPE="BUTTON" VALUE="Click Me!" onclick="startLongProcess();">
<!-- BEGIN PROGRESS DIALOG -->
<DIV STYLE="BORDER: buttonhighlight 2px outset; FONT-SIZE: 8pt; Z-INDEX:
4; FONT-FAMILY: Tahoma; POSITION: absolute; BACKGROUND-COLOR: buttonface;
DISPLAY: none; WIDTH: 350px; CURSOR: default" ID="divProgressDialog"
onselectstart="window.event.returnValue=false;">
<DIV STYLE="PADDING: 3px; FONT-WEIGHT: bolder; COLOR: captiontext;
BORDER-BOTTOM: white 2px groove; BACKGROUND-COLOR: activecaption">
加载中…… </DIV>
<DIV STYLE="PADDING: 5px">
请稍等，网页正在处理中……
</DIV>
<DIV STYLE="PADDING: 5px">
可能需要数秒钟.
</DIV>
<DIV STYLE="PADDING: 5px">
<DIV ID="divProgressOuter" STYLE="BORDER: 1px solid threedshadow;
WIDTH: 336px; HEIGHT: 15px">
<DIV ID="divProgressInner" STYLE="COLOR: white; TEXT-ALIGN:
center; BACKGROUND-COLOR: infobackground; MARGIN: 0px; WIDTH: 0px; HEIGHT:
13px;"></DIV>
</DIV>
</DIV>
<DIV STYLE="BORDER-TOP: white 2px groove; PADDING-BOTTOM: 5px; PADDING-TOP: 3px;
BACKGROUND-COLOR: buttonface; TEXT-ALIGN: center">
<INPUT STYLE="FONT-FAMILY: Tahoma; FONT-SIZE: 8pt" TYPE="button"
ID="btnCancel" onclick="stopLongProcess();" VALUE="取消">
</DIV>
</DIV>
<!-- END PROGRESS DIALOG -->
<!-- BEGIN FAKE MODAL DIV-->
<DIV ID="divModal"
STYLE="BACKGROUND-COLOR: white; FILTER: alpha(opacity=75); LEFT: 0px; POSITION:
absolute; TOP: 0px; Z-INDEX: 3"
onclick="window.event.cancelBubble=true; window.event.returnValue=false;">
</DIV>
<!-- END FAKE MODAL DIV -->
</body>
</html>
希望本文所述对大家JavaScript程序设计有所帮助。