function submitByEnter(e) {
 e = e || window.event;
 var key = e ? (e.charCode || e.keyCode) : 0;
 if(key == 13) {
                //document.getElementById("searchbtn").click();
                var keys = $("#searchkey").val();
                if($.trim(keys)!=""){
                    window.location.href="search.aspx?key="+keys;
                }
 }
}

function listen() {
     var aa = document.getElementById('searchkey');
     try{
       aa.addEventListener('keyup', submitByEnter, true);
     } catch(ex) {
       aa.attachEvent('onkeyup', submitByEnter);
     }
}