在网页上常常遇到须要等待非常久的操作，比方导出报表等。为了预防用户点击其它操作或者多次点击同个功能，须要用遮罩层把页面或者操作区盖住。防止用户进行下一步操作。同一时候能够提高界面友好度，让用户知道操作正在运行。

$.fn.extend({	/**	 * 给元素加入遮罩层	 * @param  message  {String}  [可选]遮罩层显示内容	 */	mask: function (message) {		var $target = this,			fixed = false,			targetStatic = true;		if (Object.prototype.toString.call(message) !== '[object String]' || !message) {			//假设message为空或者不是字符串，则用默认的消息提示。

message = '请稍候。

。。'; } if ($target.length === 0) { $target = $('body'); } else { if ($target.length > 1) { $target = $target.first(); } if ($target[0] === window || $target[0] === document) { $target = $('body'); } } if($target[0] === document.body){ fixed = true; } //假设目标元素已经有遮罩层，获取遮罩层 var old = $target.data('rhui.mask'); if (old) { old.$content.html(message); center($target, old.$content, fixed); return; } //假设被遮盖的元素是static。把元素改成relative if ($target.css('position') === 'static') { targetStatic = true; $target.css('position', 'relative'); } var $content, $overlay; if (fixed) { $overlay = $('<div class="rhui-mask" style="position:fixed;"></div>'); $content = $('<div class="rhui-mask-content" style="position:fixed;">' + message + '</div>'); } else { $overlay = $('<div class="rhui-mask"></div>'); $content = $('<div class="rhui-mask-content">' + message + '</div>'); } $overlay.appendTo($target); $content.appendTo($target); //显示遮罩层 $overlay.show(); $content.show(); //让遮罩层居中 center($target, $content, fixed); //把遮罩层信息加入到$target $target.data('rhui.mask', { fixed: fixed, $overlay: $overlay, $content: $content, targetStatic: targetStatic }); /** * 让遮罩层内容居中显示 * @param $target 被遮盖的元素 * @param $content 遮罩层内容元素 * @param fixed 遮罩层是否固定显示 */ function center($target, $content, fixed) { var $window, height = $content.outerHeight(true), width = $content.outerWidth(true); if (fixed) { //假设遮罩层固定显示。让遮罩层在window居中 $window = $(window); $content.css({ left: ($window.width() - width) / 2, top: ($window.height() - height) / 2 }); } else { //让遮罩层在$target中居中 $content.css({ left: ($target.width() - width) / 2, top: ($target.height() - height) / 2 }); } } }, /** * 取消遮罩层 */ unmask: function () { var $target; if (this.length === 0) { $target = $('body'); } else { $target = this.first(); if ($target[0] === window || $target[0] === document) { $target = $('body'); } } var data = $target.data('rhui.mask'); if (!data) { return; } //还原目标元素的position属性 if (data.targetStatic) { $target.css('position', 'static'); } data.$overlay.remove(); data.$content.remove(); $target.removeData('rhui.mask'); } });

插件样式由rhui-mask和rhui-mask-content类控制，rhui-mask是遮罩层样式，rhui-mask-content是遮罩层的提示内容样式。

/* 遮罩层样式 */.rhui-mask {	position: absolute;	top: 0;	right: 0;	bottom: 0;	left: 0;	z-index: 9000;	display: block;	margin: 0;	padding: 0;	border-style: none;	background-color: #777;	opacity: 0.3;	zoom: 1;	filter: alpha(opacity=30);}/* 遮罩层显示内容样式 */.rhui-mask-content {	position: absolute;	z-index: 9999;	display: block;	margin: 0;	padding: 15px 20px;	border: 2px solid rgb(109, 157, 215);	background-color: #fff;	color: blue;	letter-spacing: 2px;	font-weight: bold;	font-size: 15px;	cursor: wait;}

效果如图所看到的

页面调用完整代码

。。'; } if ($target.length === 0) { $target = $('body'); } else { if ($target.length > 1) { $target = $target.first(); } if ($target[0] === window || $target[0] === document) { $target = $('body'); } } if ($target[0] === document.body) { fixed = true; } //假设目标元素已经有遮罩层，获取遮罩层 var old = $target.data('rhui.mask'); if (old) { old.$content.html(message); center($target, old.$content, fixed); return; } //假设被遮盖的元素是static，把元素改成relative if ($target.css('position') === 'static') { targetStatic = true; $target.css('position', 'relative'); } var $content, $overlay; if (fixed) { $overlay = $('<div class="rhui-mask" style="position:fixed;"></div>'); $content = $('<div class="rhui-mask-content" style="position:fixed;">' + message + '</div>'); } else { $overlay = $('<div class="rhui-mask"></div>'); $content = $('<div class="rhui-mask-content">' + message + '</div>'); } $overlay.appendTo($target); $content.appendTo($target); //显示遮罩层 $overlay.show(); $content.show(); //让遮罩层居中 center($target, $content, fixed); //把遮罩层信息加入到$target $target.data('rhui.mask', { fixed: fixed, $overlay: $overlay, $content: $content, targetStatic: targetStatic }); /** * 让遮罩层内容居中显示 * @param $target 被遮盖的元素 * @param $content 遮罩层内容元素 * @param fixed 遮罩层是否固定显示 */ function center($target, $content, fixed) { var $window, height = $content.outerHeight(true), width = $content.outerWidth(true); if (fixed) { //假设遮罩层固定显示，让遮罩层在window居中 $window = $(window); $content.css({ left: ($window.width() - width) / 2, top: ($window.height() - height) / 2 }); } else { //让遮罩层在$target中居中 $content.css({ left: ($target.width() - width) / 2, top: ($target.height() - height) / 2 }); } } }, /** * 取消遮罩层 */ unmask: function () { var $target; if (this.length === 0) { $target = $('body'); } else { $target = this.first(); if ($target[0] === window || $target[0] === document) { $target = $('body'); } } var data = $target.data('rhui.mask'); if (!data) { return; } //还原目标元素的position属性 if (data.targetStatic) { $target.css('position', 'static'); } data.$overlay.remove(); data.$content.remove(); $target.removeData('rhui.mask'); } }); </script> </head> <body> <div id="div" style="width:600px;height:300px;margin:10px;border:1px solid red;"></div> <script type="text/javascript"> $(function () { //遮盖整个页面 //仅仅要对window、document和body使用遮罩层。都会遮盖整个页面 //$(window).mask(); //$(window).unmask(); 取消遮罩 //遮盖div $('#div').mask('载入中，请稍候。。

。'); }); </script> </body> </html>