div css background style notes

<style type = "text / CSS"> 
    .div1 { 
        width: 1024px; 
        height: 100%; 
        margin: Auto 0; 
        / * background-size: Cover; * / 
        background-Image: URL ( "$ {} the basePath / Images /t4.jpg "); 
        / * background image to be displayed only once, will not be repeated * / 
        background-rEPEAT: nO-rEPEAT; 
        / * * intermediate position in the vessel image * * /!! 
        / * background-position: Center; * / 
        / * pictures will not end with the vessel rolling and rolling * / 
        background-Attachment: Fixed; 
        / * 
        parameters: 
        Contain represent the image expanded to the maximum size so that it fully automatically adapt to the width and height of the content area, may not be filled up ; 
        cover represents the background image to expand sufficiently large to make the background image is completely cover the background, certain portions of the background image may not be displayed in the background region is positioned. 
        * / 
        Background-size: Cover; 

    } 
    .div2 {
        width: 1024px;
        background-color: rgba(110, 167, 194, 0.42);
        position: fixed;
        top:0;
    }

    .iframe{
        width:100%;
        height:100%;
        display: none;
    }

</style>