本文實例分析了jQuery遮罩層效果。分享給大家供大家參考，具體如下：
先來看看示例代碼：
<!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" xml:lang="zh" lang="zh" dir="ltr"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /></head><body><mce:script type="text/javascript" src="jquery-1.4.4.min.js" mce_src="jquery-1.4.4.min.js"></mce:script><title>Example | xHTML1.0</title><mce:style><!-- *{font-family:Arial, Helvetica, sans-serif;font-size:12px;}#full_box{background-color:gray;display:none;z-index:3;position:absolute;left:0px;top:0px;filter:Alpha(Opacity=30);/* IE */-moz-opacity:0.4;/* Moz + FF */opacity: 0.4;}#dialog{position:absolute;width:200px;height:200px;background:#F00;display:none;z-index:5;}--></mce:style><style mce_bogus="1">*{font-family:Arial, Helvetica, sans-serif;font-size:12px;}#full_box{background-color:gray;display:none;z-index:3;position:absolute;left:0px;top:0px;filter:Alpha(Opacity=30);/* IE */-moz-opacity:0.4;/* Moz + FF */opacity: 0.4;}#dialog{position:absolute;width:200px;height:200px;background:#F00;display:none;z-index:5;}</style><mce:script type="text/javascript"><!--function showBox() {var bH = $(window).height();var bW = $(window).width();$("#full_box").css({width:bW,height:bH,display:"block"});var objWH = getObjWh('dialog');var tbT = objWH.split("|")[0] + "px";var tbL = objWH.split("|")[1] + "px";$("#dialog").css({top:tbT,left:tbL,display:"block"});$("#dialog_content").html("<div style="text-align:center" mce_style="text-align:center">正在加載，請稍后...</div>");$(window).scroll(function (){ resetBox();});$(window).resize(function (){ resetBox();});}function resetBox() {var full_box = $("#full_box").css("display");if (full_box == 'block') {var bH = $(window).height();var bW = $(window).width();var objWH = getObjWh('dialog');var tbT = objWH.split("|")[0] + "px";var tbL = objWH.split("|")[1] + "px";$("#dialog").css({top:tbT,left:tbL,display:"block"});}}function getObjWh(obj) {var st = $(window).scrollTop();var sl = $(window).scrollLeft();var ch = $(window).height();var cw = $(window).width();var objH = $("#"+obj).height();var objW = $("#"+obj).width();var objT = Number(st) + (Number(ch) - Number(objH))/2;var objL = Number(sl) + (Number(cw) - Number(objW))/2;return objT +"|" +objL;}function closeBox() {$("#dialog").css("display","none");$("#full_box").css("display","none");}// --></mce:script><button id="click" onclick="showBox()">click</button><div id="full_box"></div><div id="dialog"><div id="dialog_content"></div><div style="text-align:center;" mce_style="text-align:center;"><a href="#" mce_href="#" onclick="closeBox();">關閉</a></div></div></body></html>其實遮罩層原理很簡單。
一個div 遮住下面的內容。
其中比較關鍵的一個css 樣式是
x-index: 整數值
數值越大在越上層，越小就在越下層，可以是負數。
上面的js 代碼有部分錯誤。下面已經修正。
//顯示層function showBox(id) { var bH = document.body.offsetHeight;//$(window).height(); var bW = document.body.offsetWidth;//$(window).width(); if (bH < $(window).height()) { bH = $(window).height(); } $("#full_box").css({width:bW,height:bH,display:"block"}); var objWH = getObjWh('dialog'); var tbT = objWH.split("|")[0] + "px"; var tbL = objWH.split("|")[1] + "px"; if(id=='template'){ $("#div_template").show(); }else if(id == 'history'){ $("#div_history").show(); }else{ $("#tree_"+id).show(); } $(window).scroll(function (){ resetBox(id);}); $(window).resize(function (){ resetBox(id);});}//重置層function resetBox(id) { var full_box = $("#full_box").css("display"); if (full_box == 'block') { var bH = document.body.offsetHeight;//$(window).height(); var bW = document.body.offsetWidth;//$(window).width(); if (bH < $(window).height()) { bH = $(window).height(); } var objWH = getObjWh('dialog'); var tbT = objWH.split("|")[0] + "px"; var tbL = objWH.split("|")[1] + "px"; $(".dialog").css({top:tbT,left:tbL}); $("#full_box").css({width:bW,height:bH}); }}//獲得層參數function getObjWh(obj) { var st = $(window).scrollTop(); var sl = $(window).scrollLeft(); var ch = $(window).height(); var cw = $(window).width(); var objH = $("#"+obj).height(); var objW = $("#"+obj).width(); var objT = Number(st) + (Number(ch) - Number(objH))/2; var objL = Number(sl) + (Number(cw) - Number(objW))/2; return objT +"|" +objL;}//關閉層function closeBox(id) { if(id == 'template'){ $("#div_template").hide(); }else if(id == 'history'){ $("#div_history").hide(); }else{ $("#tree_"+id).hide(); } $("#full_box").hide();}更多關于jQuery特效相關內容感興趣的讀者可查看本站專題：《jQuery常見經典特效匯總》
希望本文所述對大家jQuery程序設計有所幫助。
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