<script language="javascript" type="text/javascript">
    
    function gup(name) { name = name.replace(/[\[]/, "\\\[").replace(/[\]]/, "\\\]"); var regexS = "[\\?&]" + name + "=([^#]*)"; var regex = new RegExp(regexS); var results = regex.exec(window.location.href); if (results == null) return ""; else return results[1]; }


    function setimg() {

        adclicked = gup('ad');
        if (adclicked == 'Oil')
            document.getElementById('CouponPicture').src = 'images/OilAd.png';
        if (adclicked == 'Radiator')
            document.getElementById('CouponPicture').src = 'images/Radiator.gif';
        if (adclicked == 'Windshield')
            document.getElementById('CouponPicture').src = 'images/Windshield.gif';
        if (adclicked == 'Headlights')
            document.getElementById('CouponPicture').src = 'images/Headlights.gif';
    }

</script>