Anchor Clickable Background image in PHP, CSS

In my website, I wants to display the background image with 100% width and provide link to another website when we click the background image.

<style type="text/css">    
    #header_img a.block_link {
        display: block;
        position: absolute;
        margin:auto;
        z-index:0;
        height: 1024px;
        width: 100%;
        background-position:center top;
    }
</style>


<div id="header_img" class="header_img block block2" style="margin: 0 auto; width:100%; background-image:url(images/bgimage.jpg); background-repeat:no-repeat; background-position:center top">
    <a href="welcome.php" class="block_link" target="_blank"></a>

<div id="header_vdo" class="header_vdo" style="text-align:center; width: 100%; height:300px; margin: 0 auto; z-index:1; padding: 1px 0px 1px 0px">
Welcome to Test Page
</div>

</div>