jQuery遮罩层效果实例分析

本文实例分析了jQuery遮罩层效果。分享给大家供大家参考，具体如下：

先来看看示例代码：

<!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">正在加载，请稍后...</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();">关闭</a>
</div>
</div>
</body>
</html>

其实遮罩层原理很简单。

一个div 遮住下面的内容。

其中比较关键的一个css 样式是

x-index: 整数值

数值越大在越上层，越小就在越下层，可以是负数。

上面的js 代码有部分错误。下面已经修正。

//显示层
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);});
}
//重置层
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});
    }
}
//获得层参数
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;
}
//关闭层
function closeBox(id) {
    if(id == 'template'){
       $("#div_template").hide();
    }else if(id == 'history'){
      $("#div_history").hide();
    }else{
      $("#tree_"+id).hide();
    }
    $("#full_box").hide();
}

更多关于jQuery特效相关内容感兴趣的读者可查看本站专题：《jQuery常见经典特效汇总》

希望本文所述对大家jQuery程序设计有所帮助。