Always display the code of Div in the middle of the screen (css+js)

1. Display in the middle; (reference:sky100articles1790515)

Copy the codeThe code is as follows:

 
.ordersearchDivCss 
{ 
position: absolute; 
z-index: 100; 
display: block; 
background-color: #6ec1df; 
} 
<div class="ordersearchDivCss"  style="width: 400px; height:200px" align="center"></div> 

Js code
Call: <input type="button" onclick="sc1('DivMain')" />
// JScript file. Functions that obtain object through element id
function $(id)
{
return (id);
}

Copy the codeThe code is as follows:

 
function sc1(DivId) { 
var Div = $(DivId); 
$(DivId). = ( + ( - $(DivId).offsetHeight) / 2) + "px"; 
$(DivId). = ( + ( - $(DivId).offsetWidth) / 2) + "px"; 
//alert($(DivId).); 
} 

2. Always display in the middle. When scrolling, add the following code to Js:

Copy the codeThe code is as follows:

 
function scall() { 
sc1("DivMain"); 
} 
 = scall; 
 = scall; 
 = scall; 