on Click of Backspace Button jQuery Filter is not working
<p><strong><a href="https://jsfiddle.net/stanze/hb2zamrh/1/" rel="nofollow">DEMO HERE</a></strong></p>

<p>hi all, 
i have developed an Filtration based on JSON Data, when i type in text box Works Fine (Searches Perfect), but when i press Back Button (e.keyCode == 8) Iam Resetting all the Data.</p>

<ul>
<li><p>scenario :</p>

<p>if the User has typed (<strong>J</strong>) 2 results are displaying which is expected, if the user want to change name by some other word by pressing back button only 2 Results has to be Displayed instead of all the data.</p></li>
</ul>

<p><strong>JS :</strong> </p>

<pre><code>$(function(){
            var data = {
                "users": [
                            {
                                "id"        : 01,
                                "docName"   : "Dwayne Johnson",
                                "docCat"    : "Neurologist",
                                "docPic"    : "url('../images/01.png')"
                            },
                            {
                                "id"        : 02,
                                "docName"   : "Vin Diesel",
                                "docCat"    : "Skin Specialist",
                                "docPic"    : "url('../images/02.png')"
                            },
                            {
                                "id"        : 03,
                                "docName"   : "Paul Walker",
                                "docCat"    : "Specialist",
                                "docPic"    : "url('../images/03.png')"
                            },
                            {
                                "id"        : 04,
                                "docName"   : "Jason Statham",
                                "docCat"    : "Actor",
                                "docPic"    : "url('../images/01.png')"
                            },
                            {
                                "id"        : 05,
                                "docName"   : "Michelle Rodriguez",
                                "docCat"    : "Actress",
                                "docPic"    : "url('../images/01.png')"
                            }
                        ]
            }

            $(data.users).each(function () {
                var output = 
                    "&lt;li&gt;" + 
                        this.docName + " / " + 
                        this.docCat + " / " + 
                        this.docPic
                    "&lt;/li&gt;";
                $('#placeholder ul').append(output);
            });

            $('#search-doctor').keyup(function () {
                var doctorVal = $(this).val();
                if (doctorVal.length &gt; 0) {
                    var filterDoctor = 
                        $("li").filter(function () {
                            var str = $(this).text();
                            var re = new RegExp(doctorVal, "i");
                            var result = re.test(str);
                            if (!result) {
                                return $(this);
                            }
                    }).hide();
                    $(this).keyup(function(e){
                        if(e.keyCode == 8) {
                            $("li").show();
                        }
                    })
                } 
                else {
                    $("li").show();
                }
            });
        })
</code></pre>

<p><strong>html :</strong> </p>

<pre><code>&lt;input type="search" name="search" id="search-doctor" value="" /&gt;
    &lt;div id="placeholder"&gt;&lt;ul&gt;&lt;/ul&gt;&lt;/div&gt;
</code></pre>