jquery.min.js:2 Uncaught Error: Syntax error, unrecognized expression: #

HTML

<div class="red" id="">1</div>
<div class="red" id="2">2</div>
<div class="red" id="3">3</div>
<div class="red" id="4">4</div>
<div class="red" id="5">5</div>

Javascript

<script type="text/javascript">
$.each($(".red"), function(){
	try{
        var id = $(this).attr("id");
        $("#" + id).html("A");  
    } catch(x){
        console.log(x.toSTring());
    }

});
</script>

id가 없는 속성을 참조하려고 할 때 발생

demo : jsfiddle.net/z90rj2pn/