jquery, html5, local storage

I have the jquery script below. and it is working. however, when I try to parse to html that have two same id name. It does not show the value any more. If I put one iabel name id. it works.

How can I make more than 1 label has value from the local storage codes below?

<script>
        window.onload = function() {
            retrieveData();
            retrieveSingleData();
        };
        function retrieveData() {
            for (var i = 0, len = localStorage.length; i < len; i++) {
                var key = localStorage.key(i);
                var value = localStorage[key];
                 
                if (value == "")
                {
                    value = "Missing";
                }
                $('#' + key).html(value);
                //alert(key + " => " + value);
            }
        }       
         
</script>

<label id="test1"></label>
<label id="test1"></label>

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