How to implement pop-up layer covering the entire page using js and css_javascript skills

The example in this article describes the method of using js and css to implement a pop-up layer covering the entire page. Share it with everyone for your reference. The specific implementation method is as follows:

The common styles and structures of pop-up layers with transparent background frames are as follows:

Copy code The code is as follows:

.alertMessageBg{
position:fixed;
_position:absolute;
width:100%;
height:100%;
left:0;
top:0;
background:#000;
opacity:0.5;
-moz-opacity:0.5;
filter:alpha(opacity=50);
z-index:97;
display:none;
}
.alertMessageDivBorder{
position:fixed;
_position:absolute;
width:750px;
height:370px;
left:50%;
top:50%;
margin:-185px 0 0 -375px;
background:#000;
filter:alpha(opacity=30);
-moz-opacity:0.3;
opacity:0.3;
z-index:98;
display:none;
}
.alertMessageDiv{
position:fixed;
_position:absolute;
width:730px;
height:350px;
left:50%;
top:50%;
margin:-175px 0 0 -365px;
background:#fff;
z-index:99;
display:none;
font-size:14px;
}

How to cover the entire webpage with pop-up layer background

1.css method

Copy code The code is as follows:

.alertMessageBg{
position:fixed;
_position:absolute;
width:100%;
height:100%;
left:0;
top:0;
background:#000;
opacity:0.5;
-moz-opacity:0.5;
filter:alpha(opacity=50);
z-index:97;
display:none;
}

2.js method

Copy code The code is as follows:

.alertMessageBg{
position:absolute;
width:100%;
height:100%;
left:0;
top:0;
background:#000;
opacity:0.5;
-moz-opacity:0.5;
filter:alpha(opacity=50);
z-index:97;
display:none;
}

var bgWidth = document.body.clientWidth 'px',
bgHeight = document.body.clientHeight 'px',
alertBgNode = $('.alertMessageBg');
alertBgNode.css({'width':bgWidth,'height':bgHeight});

Comparing the above two methods, it is obvious that the css method is more trouble-free, especially now that it is not compatible with IE6.

I hope this article will be helpful to everyone’s web programming based on JS.